Detroit — Democrat Elissa Slotkin prevailed over Republican Mike Rogers in the election for Michigan's open U.S. Senate race following a contentious and hard-fought campaign.

Slotkin won the race with 48.6% of the vote to 48.3% for Rogers, with 99% of the votes counted as of 3 p.m. Wednesday, a lead of about 18,700 votes out of more than 5.5 million cast in the race. The numbers were expected to change slightly as more votes are tallied in Wayne County and elsewhere.

Green Party nominee Douglas Marsh had 1% of the vote, while Libertarian nominee Joseph Solis-Mullen of Marshall was winning about 1%, according to unofficial returns.

At a Wednesday afternoon press conference, Slotkin all but declared victory, suggesting her lead would hold even as more ballots are processed. If elected, Slotkin would be the youngest Democratic woman in the U.S. Senate, marking a "generational change," she said.

"As things stand right now, we are very confident that when the votes are counted, we will be the senator-elect for the state of Michigan," Slotkin told reporters at MotorCity Casino in Detroit.

"I'm so grateful that Michiganders have placed their trust in me and to follow in the enormous footsteps of Senator Debbie Stabenow, to represent the state that I love."

In a statement Wednesday afternoon, Rogers congratulated Slotkin, wished her the best and thanked his family and supporters.

"Michigan will always be home, and serving our state has been the honor of my life," Rogers said. "While it won’t be in the U.S. Senate right now, I will continue to serve Michigan now and into the future.

Secretary of State Jocelyn Benson's office, when asked about the thin margin between Rogers and Slotkin, said if the difference in the final tally is 2,000 votes or fewer, that would trigger an automatic recount under state law.

Coming into the decision day, Rogers and Slotkin, who both come from national security backgrounds, were locked in a blockbuster race for the seat of retiring U.S. Sen. Debbie Stabenow, D-Lansing, that evolved to rank among the most competitive and expensive contests nationally as Republicans sought to take control of the U.S. Senate. Wins in Ohio, West Virginia and Montana on Tuesday helped them do just that.

More:Here are all the 2024 Michigan election results

Rogers told a crowd of Republicans gathered at his watch party in Novi on Tuesday night that they should brace for "a very long night" as results began to trickle in. He warned not to read too much into the early returns and said his campaign doesn't detect any trends that reflect poorly on his chances yet.

"Let's do this," Rogers told the crowd at the Suburban Collection Showplace convention center. "Let's keep our spirits high. It's going to be up. It's going to be down."

Stabenow walked onto the stage at the Democratic Party's election night event in Detroit wearing a sparkly gold blazer, saying she is eager to pass her torch to Slotkin, who she says loves Michigan as much as she does.

"After tonight," the retiring senator said, "we still have to care about our democracy, we still have to care about our state, we still have to work together to move forward on all the things that we think are so very important, and we will do that together."

The race saw at least $141 million in spending by outside groups trying to sway the race, behind just three other Senate races in Ohio, Pennsylvania and Montana, according to OpenSecrets. The campaigns themselves had spent another $52 million through Oct. 16, though that figure is dominated by Slotkin, who has outraised Rogers 5:1.

Michigan was among four tossup Senate races this cycle, with Republicans increasingly targeting the Great Lakes State as a serious pickup opportunity as the year went on. The Senate Leadership Fund, a super PAC with ties to Senate Minority Leader Mitch McConnell of Kentucky, was on pace to spend $29 million to help Rogers ― all since Sept. 30.

"This is going to end up being a quarter of a billion dollar race," Adrian Hemond, CEO of the firm Grassroots Midwest, said of Michigan's Senate race.

The GOP had not won a Michigan U.S. Senate race since 1994 when former Michigan Republican Party Chairman Spence Abraham defeated former Democratic U.S. Rep. Bob Carr.

Slotkin, 48, of Holly is a former CIA analyst who served three tours in Iraq. The three-term congresswoman was a top Pentagon official appointed by former President Barack Obama who previously advised President George W. Bush on national security. Rogers, 61, of White Lake Township is a former FBI agent, Army veteran and seven-term congressman who chaired the powerful House intelligence committee.

The candidates sparred over abortion, electric vehicle mandates, immigration policy and the future of Social Security and Medicare. The campaigns also traded attacks on who is the bigger carpetbagger ― Rogers, who moved back to Michigan from Florida last year to run for Senate, or Slotkin, who moved out of her Lansing-based congressional district after a divorce last year.

Trends in exit polling

The National Election Pool conducted for news organizations by Edison Research suggested that voters made their decisions in the Senate contest on a number of hot-button issues.

Many Slotkin supporters said the top issue driving them were democracy and abortion rights, while Rogers voters were more likely to be motivated by immigration and the economy.

Slotkin was winning independent voters 52% to 45%, according to the exit polling, with a margin of error of plus-minus 3 percentage points. Slotkin was also pulling support from 6% of Republicans who voted, while Rogers was getting 4% of Democrats.

Slotkin was leading among women by a margin of 54% to Rogers' 44% and Black voters by a margin of 88% to 11%. Rogers was ahead among White voters (53% to 46%) and Hispanic voters (57% to 37%), according to the exit poll.

Slotkin was also ahead among college graduates, residents of larger cities, union households and those who believe abortion should be legal in most or all cases.

Rogers was leading among non-college graduates, suburban and rural voters and those who believe that abortion should be against the law.

On U.S. support for Israel, 45% of Slotkin voters said it was about right, 38% said it was too strong, while 9% said it wasn't strong enough. About 44% of Rogers voters said U.S. support for Israel isn't strong enough, 30% said it's about right and 20% said it's too strong, according to the exit polling.

What the voters say

Kanvana Caudle, a 53-year-old phlebotomist from Flint, said she voted for Slotkin and Democratic presidential nominee Kamala Harris, with women's rights at the top of her mind.

"The abortion issue, it's the biggest thing that I think will get people out," Caudle said after dropping off her absentee ballot at Flint City Hall. "Sometimes it's medically necessary to have an abortion, and you're gonna let these people die because of it? I don't see that."

On Slotkin, Caudle said she liked what she learned from commercials about Slotkin fighting the insurance companies when her mom got cancer. "She's been here. She's not going anywhere, and I think she's really for us, Michigan getting ahead," Caudle said.

Brian Ertsbischoff, 42, a heating and cooling system salesman from Sterling Heights, said abortion was the top issue driving his vote up and down the ballot. “I am always, usually, with whoever’s right to life. That’s where I vote,” he said.

Ertsbischoff, who opposes abortion, said he voted for Rogers “but it wasn't for any personal reasons.”

“I vote more for the values, for the morality, for what’s biblically in line with our world,” he said. “That's more important for where we vote than with my pocketbook.”

Marsha Ladd of Owosso voted a Democratic ticket during early, in-person voting Sunday, expressing enthusiasm for the top of the ticket and some disdain for the Republican Senate candidate.

“Mike Rogers is only here to keep the Senate, to keep the Republicans in power,” the 54-year-old social studies teacher said. “He already retired. He’s barely even a resident right now. I don’t have anything good to say.”

Every election, husband and wife Kat and Matt Parmelee head to the polls and “cancel each other out,” Kat said while walking into a polling place on Tuesday.

The Rochester Hills couple are divided down the ticket, including in the Senate race with Matt, 61, supporting Rogers and Kat, 57, supporting Slotkin. Both say they are concerned about the same issues, but just have different takes on how to solve them.

“We both want peace. We both want no shootings,” Matt Parmelee said. “We both believe in having a peaceful, safe life and safe country, safe world. How to get there, we disagree on.”

Jamicka Humphrey, 38, of Flint said she voted for Slotkin, saying her top issues were abortion rights and reducing gun violence and school shootings. Humphrey works in Flint Public Schools as a paraprofessional and janitor, she said.

"I'm tired of young kids dying over dumb stuff because they just let anybody getting guns these days," Humphrey said.

She added that she wants to see more women elected to public office.

"I noticed more men who are in office and they want to speak on women's rights and what women need. But I feel like if you're not a woman, you don't know what we need, right?" Humphrey said. "You can't speak about our bodies. You don't see me speaking about what a man needs, right? I'm not a man."

Julie Reid, 42, a mom from Burton, said she voted for Rogers partly because she had a negative experience when she personally interacted with Slotkin at a parade in Burton.

"I would never vote for Slotkin," Reid said. "I don't believe her. Simply, just that. On everything."

Connie Edwards, 71, a retired sixth-grade teacher from Flint, said she voted for Slotkin over Rogers.

"Mike Rogers, I know from the past, but anybody that stands with Trump, I am very concerned, very concerned. Because if you look at his character and what he has said and what he has done to this country, that is frightening," Edwards said.

"That was one of the reasons I didn't go with Mike, even though Mike's been in Michigan for years. I don't know much about Slotkin, but that pushed me towards that way."

In Genesee County, 27-year-old Lizandro Villegas, a recent transplant to Fenton from Pennsylvania, said he voted for Rogers after agreeing with the former congressman's policies. "He spoke to me a lot more than Slotkin," he said.

Candidates 'run thru the tape'

Slotkin made her closing argument to voters in recent days while riding around the state in an enormous navy blue RV named Pork Chop 3 (Slotkin's family is in the meat business). She emphasized growing the middle class, safeguarding workers rights, promoting domestic manufacturing and protecting reproductive rights.

In East Lansing this week, the site of a mass shooting last year, Slotkin also stressed the need to address school shootings, saying: "We cannot elect people who turn away from the No. 1 killer of children in America."

"We have an opportunity to come out of this period of political instability and show the world that we are better than our current politics represent," Slotkin said Monday night at a Detroit rally.

"We love our country, so wear your patriotism on your sleeve. Carry the flag, wear it proudly, and don't give an inch to the pretenders on the other side who wrap themselves in the damn flag and then spit on the values that it represents. Not an inch, not an inch."

Slotkin indicated she's encouraged by anecdotal evidence of what she calls the "secret women's vote" in Michigan. She tells the story of women putting Post-It notes or stickers on the back of women's public bathroom stalls to remind one another that their votes are private.

"It's getting to women where the men literally cannot go ― or should not go ― and it says, 'Hey, your vote is private. You don't have to tell anybody. But vote like your daughter's life is on the line.'"

mburke@detroitnews.com

Staff Writers Craig Mauger, Kalea Hall, Grant Schwab, Beth LeBlanc and Marnie Munoz contributed.