The Trump campaign filed a formal legal complaint this week with the Federal Election Commission over what the campaign calls "blatant foreign interference in the 2024 Presidential Election in the form of apparent illegal foreign national contributions made by the Labour Party of the United Kingdom, and accepted by Harris for President."

That claim remains unsubstantiated, and has been denied by both the U.K. Labour Party and its leader, British Prime Minister Keir Starmer. But lobbying firms and individual lobbyists formally registered as foreign agents of governments around the world — all with varying interests and including some autocratic regimes such as Saudi Arabia, Qatar, and the United Arab Emirates — are donating significant amounts of money to both Republican and Democratic parties and candidates in this election cycle, a CBS News analysis has found.

It is not uncommon, and not illegal, for registered foreign agents and lobbyists to finance political campaigns. Any legal permanent U.S. resident can donate to a political candidate or campaign, subject to limits imposed by the FEC.

Over $33.5 million in individual political contributions came from registered foreign agents and lobbyists during the 2020 election cycle, according to analysis conducted by the OpenSecrets organization.

But campaign finance experts say the volume of donations reviewed by CBS News and the way they're steered into American politics to serve foreign interests highlights potential loopholes in existing U.S. campaign finance laws. CBS News has reached out to all lawmakers, and donors referenced in this report for comment.

The donations and firms behind them highlighted below are likely to be just the tip of the iceberg in terms of the scale of political contributions being made by registered foreign agents, and experts say it's not just the flow of money that matters, but the conversations that take place between the entities involved.

"What I've seen in over 15 years of analyzing U.S. Foreign Agents Registration Act [FARA] filings is that there is a very, very strong correlation between whom these foreign agents are contacting and whom they're giving money to, you know, which campaigns they're giving money to," Ben Freeman, the director of the Quincy Institute's Democratizing Foreign Policy program, told CBS News.

"If they're contacting a congressional office, on behalf of a foreign power, there's a very good chance that they or somebody at their firm are also making campaign contributions to them," Freeman said.

Below are some of those firms:

Brownstein Hyatt Farber Shreck

Brownstein Hyatt Farber Schreck made $17 million in revenue for the third quarter of 2024 alone, according to Politico, citing the firm's most recent disclosure of revenue, making the company one of the most lucrative lobbyists in Washington.

OpenSecrets' most recent analysis shows the firm has taken nearly $1.3 million in total fees from foreign governments this year, with its biggest client being Saudi Arabia.

When donations from individuals related to their firm, including relatives of employees, as well as the firm's own political action committee, are taken into account, Brownstein has donated a total of $2,369,712 this year to political candidates across the country.

Around 56% of that money has gone to GOP candidates and causes, while about 42% has gone to groups and candidates affiliated with the Democrats, OpenSecrets data shows.

FARA filings reviewed by CBS News show the company is currently representing both the Saudi Ministry of Foreign Affairs and NEOM company, an investment group controlled by the Saudi government.

The principal signatory on the firm's foreign agent filings is Nadeam A. Elshami, a former chief of staff to ex House Speaker Nancy Pelosi. Federal Election Commission records show Elshami has made multiple donations to senior Democratic figures this year.

Elshami donated $2,500 in July to the Jobs, Education and Family First PAC, a political action committee affiliated with Democratic House Minority Leader Hakeem Jeffries. This PAC is a "Leadership PAC," which is a fundraising tool often established "in order to support candidates for various federal and nonfederal offices," according to the FEC.

Records show Elshami also donated $500 in June to the re-election campaign of Rep. Adam Smith, the top ranking Democrat on the House Armed Services Committee — the body responsible for funding and oversight of the U.S. Department of Defense and the United States Armed Forces.

Smith was part of a congressional delegation that met with Saudi Crown Prince Mohammed bin Salman in Jeddah in March of this year. In August, the Biden administration lifted a ban on selling offensive weapons to Saudi Arabia, reversing a three-year-old policy that had been in place to pressure the kingdom to wind down the Yemen war.

Smith told CBS News in a phone interview on Wednesday that he had not even been aware of the donation but said that it was "a bit of a stretch to take someone who is a U.S. citizen with 20 years of Hill experience, dozens of clients and say that he was acting on behalf of Saudi Arabia."

"If it's proven that Saudi Arabia or any other country for that matter is organizing an effort to get people to give money, then that's bundling and foreign countries can't do that," he added.

Elshami also donated $1,000 to the campaign of Rep. Pete Aguilar, chair of the House Democratic Caucus, responsible for electing Democratic leadership in the House, as well as $5,000 to the Democratic Congressional Campaign Committee, an official fundraising arm for House Democrats across the country.

"These aren't the biggest contributions that members of Congress are going to be receiving in terms of donations, but $1,000, $5,000, $10,000, especially in the smaller downstream races, that goes a significant way, especially in the House of Representatives," Casey Michel, author of the book "Foreign Agents: How American Lobbyists and Lawmakers Threaten Democracy Around the World," told CBS News.

Ballard Partners

Lobbying firm Ballard Partners has received around $375,000 from foreign governments this year. OpenSecrets analysis shows the Democratic Republic of the Congo has been its most lucrative client, but FARA filings show the firm has lobbied for countries including Japan, Liberia and Guatemala. The firm recently opened a new office in Saudi Arabia.

Republican megadonor Brian Ballard is the chief signatory on these foreign agent filings

This year alone, Ballard has personally donated around $250,000 to the Republican National Committee, and another $250,000 to the Trump 47 Committee PAC.

While Ballard has prolifically donated to Republican causes, he did contribute $3,300 to Sen. Chris Coons, of Delaware, in March. The following month, Coons — a top Democrat on the powerful Senate Foreign Relations Committee and a close ally of President Biden's — introduced a renewal of the African Growth and Opportunity Act, or AGOA. One of Ballard's clients, the Democratic Republic of Congo, is a beneficiary of this legislation, which grants sub-Saharan African countries duty-free access to the U.S. market.

In November 2023, months before the contribution, Coons had introduced a discussion draft of the legislation. A spokesperson for Coons told CBS News in a statement that "AGOA has had broad, bipartisan support for nearly 25 years, and Senator Coons is one of many in Congress who have routinely supported AGOA during his tenure in the Senate."

"Senator Coons believes that Americans should have confidence their legislators are not unduly influenced by foreign nations, and he would consider any FARA reform that came before the Senate," the spokesperson said.

Akin Gump Strauss Hauer & Feld LLP

The lobbying group Akin Gump Strauss Hauer & Feld has earned $5.5 million dollars from foreign government clients this year.

The United Arab Emirates is behind a sizable chunk of those fees, having paid the company $1.9 million dollars for its lobbying services on the Gulf state's behalf, according to OpenSecrets. The company has also received $1.5 million from Saudi Arabia, OpenSecrets records show.

Political contributions from individuals and their family members related to the firm, as well as the firm's own PAC donations, have totalled about $2.7 million for 2024 so far, according to an OpenSecrets analysis.

The donations have been distributed on a fairly bipartisan basis. Contributions include a total of $121,195 to the Democratic Senatorial Committee and $100,715 to the Kamala Harris campaign, and $100,625 to the National Republican Senatorial Committee.

FARA filings reviewed by CBS News show a current senior advisor for Akin Gump, Ileana Ros-Lehtinen, was lobbying on behalf of the UAE as recently as 2022.

Ros-Lehtinen is a former Florida Republican congresswoman who has made multiple donations to GOP lawmakers in this election cycle.

In February, Ros-Lehtinen made a $1,000 donation to Republican Rep. Maria Salazar, a member of the House Foreign Affairs Committee, the powerful committee with jurisdiction over bills and investigations concerning U.S. foreign affairs, as well as a $500 donation to Rep. Mario Diaz Balart, a congressman who has in the past taken a hard-line legislative stance against the Muslim Brotherhood, pushing for sanctions against the Sunni Islamist political movement. The group is fiercely opposed by the UAE.

She also donated $5,000 to Akin Gump's own political action committee in February.

"In the U.S., by far, the most common occupation for former members of Congress is to lobby other members of Congress when they leave the House or the Senate — it's more than 50%," Ben Freeman of the Quincy Institute notes.

Freeman told CBS News the cumulative effect of political donations can be sizable in terms of lobbyist influence.

"Something like $500, you know, it might not look like that much if you look at just one of these contributions at a time, but these contributions don't happen on an island. One lobbyist at the firm might make a $1,000 contribution, another one might make $2,000. The firm's PAC might make, you know, several $1,000 contributions, too," he said. "When you start adding up all the contributions from all the lobbyists and the firm itself, you start to get to some serious numbers on some of these politicians — you know, tens of thousands and even hundreds of thousands."

BGR Group

The firm BGR Group has earned $288,621 this year according to OpenSecrets. Most of that money has come from its top client, Qatar.

Individuals and PACs associated with the lobbying firm have, per OpenSecrets records, spent nearly $2 million cumulatively in campaign contributions in this election cycle.

Of that money, around $29,532 in total contributions from individuals and from the firm itself has been donated specifically to Republican Sen. Roger Wicker, the ranking member of the Senate Armed Services Committee, during 2024. It makes Wicker one of the largest individual beneficiaries of BGR contributions this year, per OpenSecrets analysis.

The Senate Armed Services Committee is currently reviewing Qatar's status as a major non-NATO U.S. ally, after a group of senators introduced legislation to revoke the Gulf state's status unless it withdraws alleged financial support for terrorist groups and expels or extradites senior Hamas leadership.

Wicker voiced opposition to the bill when it was introduced in April.

"This strikes me as a step we should be very careful about," Wicker said, according to Jewish Insider. "Qatar has been a friend in many ways and there are mutual benefits in our two countries continuing to be friends. This is a matter that governments should speak to each other about."

In a statement, Nathan Calvert, communications director for Sen. Wicker, said "support from individuals at BGR is a direct result of long-standing friendships among fellow Mississippians that precede Senator Wicker's time in elected office. Senator Wicker regularly meets with and considers the views of a wide variety of constituents and stakeholders regardless of their political support or lack thereof."

FEC filings seen by CBS News also show that BGR Government Affairs CEO Bob Wood has donated more than $42,000 to the National Republican Senatorial Committee, the official fundraising arm for the GOP's efforts to elect candidates to the U.S. Senate.

Will FARA laws change?

Recent cases involving Democratic lawmakers including former Sen. Robert Menendez of New Jersey, Rep. Henry Cuellar of Texas, and New York City Mayor Eric Adams, have exposed the potential frailties in foreign agent registry laws that could allow for foreign influence campaigns.

All three lawmakers were indicted in separate cases on charges of accepting bribes from foreign governments in exchange for official acts over the past year. Both Adams and Cuellar have pleaded not guilty to the charges and denied any wrongdoing. In July, Menendez was found guilty on all counts after being tried on charges of illegally using his influence to benefit the governments of Egypt and Qatar.

Campaign finance expert Casey Michel told CBS News that legislative efforts to reform lobbying rules seem unlikely to pass, as lawmakers are the primary beneficiaries of the existing system.

Michel noted that a whole host of legislative efforts — including a bipartisan bill called the Fighting Foreign Influence Act — have failed in Congress.

"I think the great irony in the last few years is that there have been all these bills that have been introduced, especially related to FARA and how to tighten things up, how to improve things, and none of them have passed," Michel said. "And the reason was because the chairman of the Senate Foreign Relations Committee, who was, you know, the most powerful senator in terms of crafting American foreign policy, was Bob Menendez, who, as we now know, was working simultaneously as an agent of the Egyptian government."

contributed to this report.