That swift action was praised by the acting Secret Service director, Ronald L. Rowe Jr., in remarks to reporters on Monday.

But the missed opportunity to find the gunman, identified by the authorities as Ryan W. Routh, as he lurked near the golf course has raised questions about the Secret Service’s ability to protect Mr. Trump, who enjoys his freedom and being around adoring fans.

It also heightens pressure on the agency to add resources to protect Mr. Trump in the final months of the presidential campaign, even as the Secret Service is straining under its workload in a time of threatened violence. But some lawmakers have questioned whether more money will bring about better protection.

Just two months after a different gunman fired on Mr. Trump at an outdoor rally in Butler, Pa., grazing the former president’s ear and killing an attendee, the agency once again must examine why it was unable to more decisively forestall an event that could have led to the death of the Republican nominee for president — and a national catastrophe.

Mr. Rowe said on Monday that the course had not been vetted because Mr. Trump’s golf round had been an “off the record” movement. That is Secret Service parlance for an event that had not been on Mr. Trump’s official schedule that day.

Screening a large site like a golf course, which is encircled by city streets and tall bushes like the ones where the gunman hid on Sunday, takes substantial time, Anthony Guglielmi, a Secret Service spokesman, said in an interview on Tuesday.

“An area of that size, you would need advance time to certainly sweep it and maintain the integrity of the sweeps, which means you would need to put people there, resources there, to make sure it’s kept secure,” he added.

Former Secret Service agents said there still might have been an opportunity to secure the course’s perimeter, even on relatively short notice — especially given how often agency personnel have accompanied the former president to the very same location. Mr. Trump routinely plays golf of Sundays, often at his Florida clubs.

“He’s a creature of habit, and I think you sort of lose the element of surprise when he’s using one of his golf courses that are in close proximity,” said Jonathan Wackrow, a longtime Secret Service agent who is now in private security.

During a campaign stop in Sparta, Mich., on Tuesday, Senator JD Vance, Mr. Trump’s running mate, denounced the Secret Service for inadequately protecting the former president. “Donald Trump ought to have the same detail as Joe Biden,” Mr. Vance said, “but our federal government has decided that Donald Trump deserves a lesser level of protection.”

Vice President Kamala Harris, who was campaigning in Philadelphia, struck a different tone. “Yes, I feel safe,” she said during an interview with members of the National Association of Black Journalists. “I have Secret Service protection. But that doesn’t change my perspective on the importance of fighting for the safety of everybody in our country and doing everything we can to again lift people up.”

Off-the-record stops, which are common for presidents, vice presidents and other protectees, are typical features of a Secret Service schedule. They are generally impromptu moments in which a protectee wants to change up the schedule to take a needed jog, grab a bite at a restaurant or stop by a friend’s house.

The agency has procedures for handling those situations, current and former agency officials say, including the use of plainclothes agents who do countersurveillance and the strategic positioning of agents around the protected person to keep potential harm doers away.

During an off-the-record stop in July, Ms. Harris, who had not yet been named the Democratic nominee for president, walked into an indoor farmers’ market in Philadelphia with Pennsylvania’s governor, Josh Shapiro. No walk-through metal detectors were posted at the door to sweep members of the crowd to discover concealed weapons, and throngs of shoppers stood nearby as Ms. Harris ordered salmon curry at the Little Thai Market.

Despite the number of people in close proximity to her, the agency said measures were taken that day to protect her that were unnoticeable to the broader public.

“U.S. Secret Service protectees visit a variety of environments as part of their duties,” Mr. Guglielmi said. “Our teams are trained to adapt our protective measures for all events and locations. In this case, U.S. Secret Service determined that the vice president and members of her staff could safely accomplish the visit.”

On Sunday, service members used what service employees call their “layered” approach to keep Mr. Trump safe, including posting countersnipers who could shoot at a potential assailant, counterassault teams who could fight off a larger attack and aerial surveillance.

Critically for Mr. Trump on Sunday, the service also deployed a small team of agents to walk a hole or two ahead of him on the course. That allowed a site agent in that group to spot and then fire on Mr. Routh, who allegedly had a gun trained in the direction of Mr. Trump through a thatch of shrubbery. Mr. Routh was apprehended less than an hour later, after being pulled over on Interstate 95.

The House task force investigating the July assassination attempt against Mr. Trump demanded interviews and documents from the F.B.I. on Tuesday as it began expanding its inquiry to include the second potential attempt on Mr. Trump’s life.

In a letter to Attorney General Merrick B. Garland and Christopher A. Wray, the F.B.I. director, the leaders of the panel asked the bureau to brief lawmakers by Friday on the more recent assassination attempt.

Speaker Mike Johnson said he planned to alter the structure of the task force to investigate both the shooting of Mr. Trump in Pennsylvania and this weekend’s attempt in Florida.

“We’re going to change the emphasis of that to have both events investigated,” Mr. Johnson said at an event at the America First Policy Institute.

Mr. Johnson added that he did not believe funding issues had hampered the Secret Service. Instead, he said, the problems at the agency stemmed from a “lack of leadership.”

Republican senators held a news conference on Tuesday to condemn the golf course episode, and call on the Secret Service to provide equal protection to Mr. Biden and Mr. Trump. Former presidents and nominees have a lesser level of security than presidents.

On Monday, Senator Chuck Schumer, Democrat of New York and the majority leader, said he would be open to providing more funding to the Secret Service. So far, there has not been a specific proposal for additional funds.

Michael C. Bender and Nicholas Nehamas contributed reporting.

The episode concluded after about two hours, with the president and the hostages unhurt. But Reagan decided that his time as the nation’s golfer in chief was largely done.

“Playing golf is not worth the chance that someone could get killed,” he said, according to Joseph Petro, a longtime member of Reagan’s protective detail who recounted the incident in his 2005 book, “Standing Next to History: An Agent’s Life Inside the Secret Service.” Reagan rarely played again.

Most recent American presidents have embraced golf as a bipartisan tradition — a head-clearing, backslapping escape where a president is just as likely as anyone else to be betrayed by a putter. But just as the Reagan episode prompted the White House to rethink whether presidential golf rounds invited unnecessary risks, Sunday’s apparently thwarted assassination attempt on former President Donald J. Trump has sparked questions about the perils that come with navigating 18 holes across wide-open spaces.

Presidents and their Secret Service agents have been trying for decades to balance security risks with the need for sporting refuges. But Mr. Trump’s approach to golf — including his frequency of play and his overt preferences for a handful of courses — has posed especially steep challenges for the Secret Service, which gets nervous when someone it guards settles into predictable patterns.

After Sunday’s possible attempt at Trump International Golf Club West Palm Beach, the Secret Service’s acting director privately told Mr. Trump that the agency would need to take significant new steps to protect him if he continued to play. The warning from the agency, which deploys fewer resources for former presidents than it does an incumbent, raised the possibility that Mr. Trump could adjust where or how often he plays.

Mr. Trump usually plays his own courses, some of which have lately hosted tournaments for the Saudi-backed LIV Golf league.

Some courses pose greater risks than others. At one near Washington, for example, boaters have drifted past on the Potomac River within sight of Mr. Trump. And the course in West Palm Beach is close to public roads. Other properties are more isolated, with fewer obvious opportunities for a would-be assailant to draw close to the former president.

But they are still golf courses with few fortified shelters. Mr. Trump typically drives his own cart when he plays, and his courses generally remain open when he’s nearby, with players and other visitors free to gawk at, and often approach, the former president. He is prone to interrupting his rounds to sign autographs, pose for photographs and hold rolling news conferences to inject himself into the national conversation. (At the Virginia course last year, for example, he approached a reporter for The New York Times, his iPhone in hand, to show that he was on the line with Kevin McCarthy, who was then the House speaker and struggling with a debt ceiling debate.)

Sitting and former presidents, who receive lifetime protection from the Secret Service, have usually adopted lower profile approaches to golf — whether for security or to blunt the political risks of playing a sport often associated with exclusivity. (There is also the danger of a wayward shot becoming comedic fodder for the masses).

President Biden has only sporadically played since he arrived in the Oval Office, which did not keep him and Mr. Trump from squabbling on the debate stage in June over who was the superior golfer.

During his eight years in power, Barack Obama was a regular on a course at a military base near Washington, with reporters and photographers rarely allowed to glimpse his rounds.

George W. Bush said in a 2008 interview with Politico and Yahoo News that he had stopped playing during the Iraq war because “I don’t want some mom whose son may have recently died to see the commander in chief playing golf.” But Mr. Bush also received sharp criticism years earlier when, at the start of a round, he spoke to reporters about a bombing in Israel and concluded: “I call upon all nations to do everything they can to stop these terrorist killers. Thank you. Now watch this drive.”

Bill Clinton was an irrepressible golfer who relished how his office made him an appealing playing partner. Professional players were eager to join him and offer advice. Near the end of Mr. Clinton’s final term, Mr. Trump invited him to join one of his clubs; he accepted.

Decades earlier, before Gerald R. Ford started hosting pro-am tournaments, Eisenhower was the president who seemingly could not stop playing — so much so that his immediate successor, John F. Kennedy, a more skillful golfer than many of his presidential counterparts, was self-conscious about being seen on a course.

“Approaching the ninth green, the president spotted a whole raft of photographers just kind of over the crest of the green,” Paul B. Fay, a Kennedy friend who served in his administration, remembered in an oral history for the Kennedy Library. “He just turned at that time and said, ‘I just don’t want to have my picture taken, one of the first things of my administration, playing golf. I’m going to leave.’”

Mr. Trump has shown far less reserve, particularly since he left the White House. There have been times, though, when he has seemed to savor the game’s pleasures or the moments of relative calm it offered.

On that much, he and Mr. Clinton might have common ground.

“Even though you’ve got these Secret Service people all around us,” Mr. Clinton once told Golf Digest, “this is the nearest I ever am to being like a normal person.”

The meeting came just 24 hours after a second apparent assassination attempt on Mr. Trump within just two months. Behind the scenes, tensions between the Trump campaign and the Secret Service had already been escalating.

Mr. Trump asked Mr. Rowe whether it was safe for him to keep playing golf, one of the people said. Mr. Rowe discussed the difficulties of securing sprawling golf courses near public roads and said some of Mr. Trump’s courses were easier to protect than others, one of the people said.

It is unclear what changes Mr. Trump will make to his golf schedule, and some people in Mr. Trump’s orbit are frustrated at any notion he might have to cut back on his weekly activity. They questioned why President Biden was able to visit open beaches but Mr. Trump should have to restrict his golf, especially given that other former presidents regularly play the sport.

However, Mr. Trump and Mr. Biden do not receive the same level of security. One of them is a sitting president and one is a former president. Mr. Trump’s level of Secret Service protection was reduced after he left the White House. But since the first attempt on Mr. Trump’s life in July in Butler, Pa., both Republican and Democratic lawmakers have raised concerns about his protection, given the current intensity of threats. Mr. Biden has called on the Secret Service to provide whatever additional resources are required to keep Mr. Trump safe.

Golf remains more than a pastime for Mr. Trump — it’s a major part of his identity as well as a way of socializing and a release valve as he faces a presidential campaign and ongoing legal woes.

The authorities said the suspect in the latest case, Ryan W. Routh, hid for 12 hours on Sunday near the Trump International Golf Club in West Palm Beach. After a Secret Service agent spotted Mr. Routh poking the barrel of a gun through bushes on the course’s perimeter, that agent opened fire, leading Mr. Routh to run to his car, officials have said.

Mr. Routh left behind a semiautomatic rifle, a scope, two backpacks and a GoPro camera, which suggested he intended to film a shooting, officials said. The police pulled him over on the side of the Interstate 95 about 45 minutes after a witness, who saw him fleeing, photographed his license plate.

In their meeting on Monday, Mr. Rowe told Mr. Trump that it was difficult to secure his sprawling golf courses because they have so much open space, one of the people briefed on the meeting said.

The courses are close to public roads and the fact that photographers, using long-range lenses, can often capture Mr. Trump on his greens and fairways suggest that a skilled gunman might be able to get a clear line of sight on him. Mr. Trump raised some of these concerns himself in the meeting with Mr. Rowe, one of the people with knowledge of the meeting said.

Mr. Rowe told Mr. Trump that the Secret Service views the golf course at Joint Base Andrews as easier to secure than some of his courses, because it’s a military course, two of the people said. Barack Obama frequently played there during his presidency.

Given Mr. Trump’s campaign schedule, which is expected to be busier as the November election draws near, it is unclear how much golf he will be able to play in the final 49 days, an adviser said.

A campaign spokeswoman, Danielle Alvarez, declined to comment on Monday’s private briefing. She noted Mr. Trump’s Sunday post on social media, in which he praised the Secret Service and law enforcement.

“It was certainly an interesting day!” Mr. Trump wrote on Truth Social, adding in all-caps, “The job done was absolutely outstanding.”

In a private conversation on Sunday, Mr. Trump told Senator Lindsey Graham that his Secret Service team had been “awesome,” Mr. Graham, Republican of South Carolina, later recalled.

But while Mr. Trump has repeatedly praised the agents on his personal detail since the first assassination attempt in July, his team has complained that the agency has not provided him with the resources the campaign has requested.

Mr. Trump had a private call with President Biden on Monday, according to two people briefed on the matter. During the call, according to one of those people, Mr. Biden referred to an uptick in concerning episodes affecting Mr. Trump. Mr. Biden said he was committed to giving all the resources necessary, but that additional congressional funding was required.

Mr. Trump said his Secret Service detail said they could use more people, the person said. Mr. Biden said that’s what congressional funding would do, the person said.

A spokesman for the Secret Service said Mr. Rowe declined to comment on private conversations involving someone the agency protects.

Mr. Trump owns or leases a number of courses, including three in Florida, as well as one in New Jersey, one in Westchester County in New York, one in Sterling, Va., two courses in Scotland and one in Ireland, and a new one in the Middle East. He plays every week and takes great pride in it, describing it as his main form of exercise.

Aides to Mr. Trump have described golf as an important form of relaxation for him. When he was cooped up in a Manhattan courtroom for his hush-money trial this year, his advisers were eager for him to spend as much time as possible on his golf courses.

As president, Mr. Trump often used his Virginia club, and sometimes took lawmakers out on the golf course with him. Since leaving the presidency, Mr. Trump has played his courses with sports figures, donors and supporters, and mingles openly with people in the club dining rooms. The golf courses have been one of Mr. Trump’s steadiest streams of income.

After the first assassination attempt in July, when a 20-year-old man, Thomas Crooks, came within inches of killing Mr. Trump at a rally in Butler, Mr. Trump told allies that the Secret Service had concerns about him playing golf. But Mr. Trump continued to play.

The Secret Service has come under harsh scrutiny over security lapses that allowed Mr. Crooks to crawl onto a warehouse rooftop at the July 13 rally in Butler and fire off eight rounds at Mr. Trump, wounding his ear and killing a spectator in the crowd behind him. The agency appears to have narrowly averted another shooting at Mr. Trump on Sunday by posting agents ahead of the former president to scout out his next holes on the golf course. Agents were able to spot and shoot at the would-be assailant before he could fire his own weapon through the shrubbery.

The suspect, Mr. Routh, has been known to U.S. authorities in recent years. A contractor and occasional social activist, Mr. Routh has a significant criminal record, including a 2002 conviction in North Carolina for possessing a weapon of mass destruction, which court records describe as explosives with a blasting cap and detonation cord.

Mr. Trump has also been the target of foreign assassination plots, particularly from Iran. U.S. officials obtained information about an Iranian plot to assassinate Mr. Trump in the weeks ahead of the Butler rally, although the plot did not appear connected to the shooting that took place.

The former head of the Secret Service, Kimberly A. Cheatle, resigned her post while facing widespread criticism of the agency over the Butler attack.

The acting director of the Secret Service, Mr. Rowe, said in a Monday news conference that “the protective methodologies of the Secret Service were effective yesterday,” but he also made it clear that the agency did not search the golf course’s perimeter before Mr. Trump began his round.

“The president wasn’t even really supposed to go there,” Mr. Rowe said. “It was not on his official schedule.”

But it is well known that Mr. Trump frequently golfs at his course in West Palm Beach when he’s staying at Mar-a-Lago. It remains unclear why no perimeter search was conducted.

Mr. Routh, 58, ran a business called Camp Box Honolulu, which aimed to cheaply and quickly build mobile homes small enough to avoid what his website called Honolulu’s onerous and “overloaded” permitting process, according to his website.

He lived for decades in North Carolina before he moved to Hawaii several years ago, a residency that was broken up by travel to Ukraine in 2023 to assist the war effort. His letters to the editor first appeared in the Honolulu Star-Advertiser in 2018, and state records indicate that he filed business paperwork for Camp Box Honolulu in January 2019.

In the small town of Kaaawa, Hawaii, neighbors this week described him as a handyman who was often eager to help in the community, though many said they never really got to know Mr. Routh.

David Stant, 61, who lived down the street, described Mr. Routh as a nice but quiet man, while Mr. Routh’s partner, Kathleen Shaffer, was more extroverted. Mr. Routh was a skilled builder who renovated his own home largely by himself and built tiny homes in the front driveway, Mr. Stant said.

Another neighbor, Raymond Correa, 58, described Mr. Routh as “straight up.”

“If you needed help, he’d come help you, bring out his nail gun and start going at,” Mr. Correa said. “I never knew if he was a Republican or Democrat.”

Charles Aipia, 78, lived a few houses down from Mr. Routh and Ms. Shaffer. He said he sometimes had the couple over for karaoke, and Mr. Routh often helped with repairs around town, once repairing a leaky roof for Mr. Aipia’s former wife.

But he also described a dispute in which Mr. Routh recently used a hose to spray a dog that belonged to Mr. Aipia’s granddaughter because it was barking in her yard.

“He soaked all the bedding and everything, the dog was shaking, soaking wet,” Mr. Aipia recalled. “He didn’t apologize to my granddaughter.”

“After that, we didn’t talk,” Mr. Aipia said.

Nonetheless, Mr. Aipia said that he would never have thought Mr. Routh would be a suspect in a possible attempted assassination. “Something must have snapped,” he said.

In 2019, Mr. Routh, as the owner of Camp Box, told the Honolulu Star Advertiser about his efforts to build shelter for homeless residents. From 2018 to 2020, he provided roofs and floors for tiny homes developed by the nonprofit HomeAid Hawai’i, according to a statement from the organization’s executive director, Kimo Carvalho.

“He was not compensated, and no complaints were recorded during his time with us under HomeAid Hawai‘i’s previous leadership,” Mr. Carvalho said.

On its website, Camp Box advertises a menu of bare-bones structures: $1,500 would get customers a 4-foot by 8-foot tiny home with a door and two windows. For $2,500, they would get an 8-foot by 8-foot tiny home with electricity.

But the site warns that the Honolulu city government doesn’t allow small structures to have hard wiring without a permit. As a result, it says, the electrical wiring is categorized as “a free bonus that is not guaranteed in any fashion.”

A “Customer Relations” page includes a 9,703-word explanation of Camp Box’s philosophy, signed at the end by “Ryan Routh.” The essay at different points portrays customers who ask about the quality of his work as “cheap,” “selfish” or “greedy.” He warns customers that they may find imperfections in the structures: Uneven floors are inevitable, he insists, and nails or staples may protrude from walls. He tells customers that his crews clean up only when time permits.

“We focus solely on an economical product that is created fast and efficiently with little or no profit, and while our units, through mass production get more refined,” Mr. Routh writes. “Perfection is nothing that we will ever guarantee, so griping and complaining about anything is not allowed!!!!!!!”

In some sentences, he professes a kind of altruism: He claims that he neither expects nor needs to make money from the enterprise and that his motivation is to provide housing for his neighbors.

But he also lamented the state of the American work ethic. And he railed against government bureaucracy, and the idea that those who complain dictate too much of how the world runs.

The voice mailbox for the business was full on Monday. According to the site, Mr. Routh ran the business with his son, Adam, who did not respond to a phone call on Monday.

Curtis Lum, a spokesman for the Honolulu Department of Planning and Permitting, said in an email that the office has “no record of any building permits or complaints relating to Ryan Routh and his Camp Box business.”

But Mr. Lum said the Camp Box website was inaccurate when it suggested that building permits were not required. He said that any structure intended for habitation requires a building permit, regardless of size, and that permits are required for any electrical or plumbing hookups.

At the address listed on Camp Box Honolulu’s website, along a stretch of busy highway in nearby Kaneohe, a vacant lot was surrounded by trees and bushes — and no signs of his business.

Kaiulani Clark, 57, who runs a coconut stand nearby and occasionally works at a plant nursery next to the vacant lot, said that Mr. Routh had not been at the site for at least two years.

When he was there, Mr. Routh worked with perhaps three other men at the site, Ms. Clark said. She only recalled seeing two homes being built, which she described as low-quality structures with crooked windows.

“He seemed like a shoddy guy,” she said. “He just never did finish anything.”

Michael Corkery contributed reporting, and Susan C. Beachy contributed research.

While the agency’s acting director hailed a Secret Service agent for acting swiftly and preventing any harm to Mr. Trump on Sunday, the F.B.I. said that data from a gunman’s cellphone indicated he spent almost 12 hours near the course before he aimed a rifle in the direction of Mr. Trump while he was golfing.

In remarks to reporters at the Palm Beach County Sheriff’s Office on Monday afternoon, Ronald L. Rowe Jr., the Secret Service’s acting director, said, “The president wasn’t even really supposed to go there.”

Mr. Rowe said Mr. Trump, the Republican presidential nominee, did not have an outing on the course on his official schedule. Mr. Rowe did not clarify in his statements whether this meant that agents did not have time to sweep the golf course. Yet it is public knowledge that Mr. Trump frequently plays golf at one of his Florida courses on Sundays, raising the risk level for the former president.

Mr. Rowe praised his agents for spotting the barrel of a gun poking through the bushes of the golf club and firing at the suspect, Ryan W. Routh, 58, before he could get off a shot. A manhunt commenced, leading to Mr. Routh being detained soon after. He was charged in federal court on Monday with possession of a firearm as a felon.

The Secret Service’s methods “were effective yesterday,” Mr. Rowe said. He pointed to “early” identification of the threat, an immediate evacuation of Mr. Trump and the help of increased protective measures — including the presence of countersnipers.

But after Sunday’s episode, legislators, law enforcement officials and Secret Service alumni questioned whether the embattled agency was still up to its mission of protecting current and former presidents and their families.

“I’m very concerned at reports that the suspect allegedly was in the bushes for 11 hours,” said Beth Celestini, a longtime Secret Service agent who protected President Barack Obama before retiring in 2021. “The Secret Service has protocols where if enacted, this suspect should have been discovered before the incident.”

Ronald Layton, a 26-year veteran of the agency who led divisions with oversight of protection and event security, asked, “Was this just luck that you caught this guy, or did you have the appropriate mechanisms in place for these kinds of things on the threat spectrum?”

Mr. Rowe said that in order to handle an increasingly challenging threat environment, the Secret Service would need Congress to provide more funding for personnel, overtime and facilities.

His appeal had already received the endorsement of President Biden, who had told White House reporters on Monday morning that “the Service needs more help” and that Congress “should respond to their needs.”

Aides involved with the Senate and House Appropriations Committees, who requested anonymity because they were not authorized to disclose private discussions, said the panels were reviewing the Secret Service’s requests.

At the same time, top House officials are considering whether to hold a vote to expand the jurisdiction of an investigative task force to include Sunday’s events, according to two people familiar with the matter. The House task force is investigating the circumstances of the July 13 shooting in Butler, Pa., in which a would-be assassin, Thomas Crooks of Bethel Park, Pa., shot at Mr. Trump during a campaign rally.

Mr. Trump’s ear was grazed and a rallygoer was killed. It is unclear whether the episode in West Palm Beach was also within the task force’s jurisdiction.

The Secret Service is now undertaking its second internal review in two months, hoping to determine whether it handled the events of Sunday properly.

The agents who are tasked with protecting current and former presidents and their families are working long hours with little reprieve.

In addition to protecting foreign leaders who visit the United States, the Secret Service guards more than 40 people: Mr. Biden, Vice President Kamala Harris, Mr. Trump, other former presidents and their immediate families. An increase in hate speech and violent threats has complicated the agency’s mission.

Since Butler, the Secret Service has reassigned members of Mr. Biden’s advance team to Mr. Trump and Ms. Harris, provided special glass to surround Mr. Trump during campaign events and received additional resources from the Pentagon. Its parent agency, the Department of Homeland Security, has also deployed 1,500 investigations agents of its own to bolster the Secret Service’s ranks.

Chronic personnel shortages, worsened by the job’s long and sometimes grueling hours, have left the Secret Service both short-handed and underfunded in areas like facilities and technology.

In response to offers from lawmakers to provide additional funding, Mr. Rowe also wrote to two senators this month — before Sunday’s close call.

“The increased mission requirements of the Secret Service necessitate additional resources to ensure that we have the tools, resources and personnel needed to meet these new requirements,” Mr. Rowe wrote in the Sept. 5 letter.

Those resources, which were detailed in additional pages of the letter that have not been reviewed by The New York Times, do not appear to have come through yet. But on Monday, Mr. Rowe said he was optimistic they would.

“Success, we have to have it every day. We cannot have failures,” he said. “And in order to do that, we’re going to have some hard conversations with Congress.”

Reporting was contributed by Eileen Sullivan , Hamed Aleaziz , Luke Broadwater and Audra D. S. Burch .