This article was co-published with the American Prospect.

When expert witnesses appear before congressional committees, they must disclose certain details about their funding, including federal grants or contracts or money they’ve received from foreign governments. That applies to the expert and the institution they’re representing. These Truth in Testimony rules are intended to ensure that committee members and the general public are given a full picture of the financial interests behind witness testimonies. It is a federal crime to withhold information from the committees.

Earlier this month, the House of Representatives Committee on Rules strengthened the Truth in Testimony rule requiring witnesses offering testimony to disclose whether they are the fiduciary of any entity with a financial interest in the subject matter of the hearing, a level of disclosure of potential financial conflicts of interests that was not previously required. Witnesses will also need to disclose if entities they represent received grants or contracts from foreign sources. The new changes will offer greater accountability and insight into the financial interests behind expert witnesses at congressional hearings.

That doesn’t necessarily mean that transparency will win the day. Take, for example, the House Foreign Affairs Committee. An ideologically narrow group of think tanks, many of which refuse to reveal their funding sources, have dominated the witness table, raising uncertainty about how much transparency the new rules will bring about.

The new rules mean that those think tanks may have to further disclose federal grants and foreign funding if it’s related to the subject matter of hearings. But their opaque donor lists pose challenges for actual accountability and enforcement. Since the new rules require witnesses to self-identify potential conflicts of interest without offering a more comprehensive disclosure of their funding sources, members of Congress and the public are largely relying on the witnesses themselves to be the sole adjudicator of what constitutes a conflict of interest requiring disclosure.

“Hearings are opportunities to get answers for the American people—we need to know about foreign influence or any risk of self dealing with the witnesses called before Congress,” Rep. Katie Porter (D-Calif.) said in a press release. “The new rules will also give members of Congress the opportunity to raise questions about special interests in the course of hearings.”

A large number of those witnesses work for or are officers at Washington think tanks, and not enough is known or disclosed about how their financial interests influence testimony. A review of 622 nongovernmental witnesses appearing before the House Foreign Affairs Committee over the past two congressional sessions found that think tanks were one of the most common sources of expert testimony, accounting for over one-third, or 237, of the witnesses.

Congress and the general public have surprisingly little insight into who pays the salaries of experts affiliated with nonpartisan and nonprofit policy research institutions or who funds the institutions with which they are affiliated. Instead, we have to rely on the institutions’ voluntary disclosures on their websites or in the limited instances required on Truth in Testimony disclosures.

And these research institutions’ self-disclosures leave much to be desired. Of the 237 think tank–affiliated witnesses who spoke before the House Foreign Affairs Committee, under 30 percent of think tank–affiliated witnesses appeared on behalf of institutions that fully disclose their donors.

A small number of think tanks dominate the witness table, and they happen to be institutions that are particularly opaque about their funders. Four think tanks accounted for about one-third of all expert witnesses at the House Foreign Affairs Committee in the past two Congresses, and each of those institutions demands further scrutiny.

The Center for Strategic and International Studies led the pack, with its staff appearing 29 times before the committee since 2017.

CSIS’s relative transparency about its funding, at least in theory, should make the new Truth in Testimony rules relatively easy to enforce. It provides a comprehensive list of its funders for public review, revealing foreign government, defense contractors, and oil and gas related sources of funding.

But by putting the burden of disclosure on the expert witness, there is still too much wiggle room. For example, if a CSIS-affiliated witness testifies about a region from which CSIS received foreign funding, the witness might be expected to disclose that foreign funding in the Truth in Testimony disclosure. If a CSIS-affiliated witness failed to disclose that potential conflict of interest on their Truth in Testimony form, members of Congress and the general public have the necessary information to cross-reference CSIS’s publicly disclosed donor rolls for any discrepancies with the witness’s Truth in Testimony disclosures. But that level of disclosure is far from the norm for the other think tanks most frequently appearing before the House Foreign Affairs Committee.

The other three think tanks most frequently invited to House Foreign Affairs Committee hearings provide incomplete, or no, information about their funding. They also promote narrow and militaristic U.S. foreign policies, including U.S.-led regime change in Iran, defending unconditional U.S. support for Israel, and supporting a hawkish U.S. strategy around the world.

The Heritage Foundation is a right-wing juggernaut that emerged as one of the most doggedly pro-Trump institutions over the past four years, playing a central role in staffing the administration. According to an investigation conducted in 2018, at least 66 Heritage employees and alumni had entered the administration. And they were extremely well represented before the House Foreign Affairs Committee.

Heritage experts testified before the House Foreign Affairs Committee 12 times during the Republican-controlled 115th Congress and five times during the Democratic-controlled 116th Congress.

Heritage publishes a donor list but conceals the identity of certain donors, listing them as “anonymous,” including 20 who in 2019 donated up to a half-million dollars, and 13 other donors in 2018 who gave the organization up to a half-million.

Heritage did not respond to a request for comment about their selective donor disclosure.

All of this poses questions about their impartiality. Consider the group’s ties to foreign interests, with a particular interest in international law around autonomous weapons systems and the international mine ban treaty disclosed last year when it was revealed that between 2007 and 2015, Heritage received at least $5.8 million from the Hanwha Group, a South Korean conglomerate that produced land mines and a controversial autonomous weapons system. Heritage had not disclosed its funding from Hanwha when opposing international efforts to ban anti-personnel land mines, cluster munitions, and “killer robots” like those manufactured by Hanwha.

Experts from the staunchly pro-Israel Washington Institute for Near East Policy, a think tank formed in 1985 with support from the pro-Israel lobbying powerhouse American Israel Public Affairs Committee, testified 16 times before the House Foreign Affairs Committee in recent years.

WINEP reveals no information about the donors who fund its $14.7 million annual budget. This does a disservice to the American public who rely on the Institute’s expertise in front of their representatives in the committee room.

"As an American interest think tank, The Washington Institute maintains a longstanding policy of accepting no donations from foreign governments, individuals, corporations, foundations or institutions,” said WINEP Executive Director Robert Satloff when asked about the group’s lack of transparency. “We rely on Americans to support our work."

Finally, the Foundation for Defense of Democracies is a hawkish think tank that regularly advocates for U.S.-led military action against Iran, vigorously opposed the Obama administration’s efforts to negotiate limitations on Iran’s nuclear program, and participated in a now-shuttered State Department–funded program to attack American critics of the Trump administration’s foreign policy.

The group, whose original mission statement included “provid[ing] education to enhance Israel’s image in North America and the public’s understanding of issues affecting Israeli-Arab relations,” and whose 2003 website falsely stated, “We know Saddam Hussein is making weapons of mass destruction,” testified 12 times before the House Foreign Affairs Committee during the Republican-controlled 115th Congress and three times during the Democratic-controlled 116th Congress.

In 2017, FDD received funds from Trump fundraiser Elliot Broidy to host a conference on Qatar’s alleged ties to Islamic extremism. Broidy’s funds had originated from the United Arab Emirates, Qatar’s regional rival, a fact FDD officials say was not shared with them and goes against their policies. FDD’s revenue jumped from $12.2 million in 2018 to $32.5 million in 2019, only adding to the questions about its funding sources, since the organization provides no information about those sources.

FDD did not respond to a request for comment about its refusal to disclose sources of funding.

Experts say it will be difficult to diversify the voices that present expert testimony. Committee leaders have grown accustomed to hearing from the slickest and best-funded institutions in Washington.

But the lack of transparency from some of those institutions might be something that a single member of a committee could quickly resolve if they were so inclined.

“If I was a member of Congress,” said Ben Freeman of the Center for International Policy, “my first question to a think tank witness, under oath, might be to provide a list of their funders if their organization doesn’t publicly provide their donor list.”

Such a question, posed to witnesses affiliated with think tanks that choose not to disclose their funding sources, could be a first step in determining whether witnesses are violating federal law by omitting relevant disclosures from their Truth in Testimony disclosures.