Two House Republicans endorsed a Democratic effort on Friday calling on the House and Senate committees with oversight of the Internal Revenue Service to request copies of President Trump’s tax returns.

Reps. Mark Sanford (R-S.C.) and Walter Jones (R-N.C.) signed a letter urging the chairmen of the House Ways and Means Committee and Senate Finance Committee to ask for copies of Trump’s tax documents from the last decade.

The letter was spearheaded by Rep. Bill Pascrell (D-N.J.) and signed by most of the 193-member House Democratic Caucus. It argues that letting members of Congress see what’s in Trump’s tax returns would clear up any questions about whether his business ties offer conflicts of interest.

{mosads}Trump broke with four decades of precedent by refusing to release his tax returns after becoming the GOP presidential nominee. He cited an ongoing IRS audit, though the agency has said taxpayers are free to release their information at any time.

“Disclosure would serve the public interest of clarifying President Trump’s conflicts of interest in office, the potential for him to personally benefit from tax reform, and ensure that he is not receiving any preferential treatment from the IRS,” the letter states.

“We believe the powerful and respected Committees on Finance and Ways and Means have the responsibility to ensure oversight of the executive branch by requesting a review of President Trump’s tax returns and moving toward a formal release of these documents to the public.”

Earlier this week, Pascrell forced a House vote on a resolution requesting the last ten years of President Trump’s tax returns. It failed on a party-line vote, but Sanford and Jones both voted “present.”

Sanford has called for Trump to release his tax returns, including in a New York Times op-ed last year.

Pascrell’s resolution specifically would have directed the House to request Trump’s tax returns and have the House Ways and Means Committee review them in a closed session. The panel would then vote to send the information contained in the returns to the full House. 

The House Ways and Means and Senate Finance committees, along with the Joint Committee on Taxation, have the power to request individual tax returns from the Treasury Department. 

But the chairmen of those committees have dismissed the idea.

Senate Finance Committee Chairman Orrin Hatch (R-Utah) rejected a request from Democrats to ask for copies of the president’s tax returns. 

And House Ways and Means Committee Chairman Kevin Brady (R-Texas) has cited privacy concerns in explaining why he wouldn’t set a precedent of requesting Trump’s tax returns.

“My belief is that if Congress begins to use its powers to rummage around in the tax returns of a president, what prevents Congress from doing the same to average Americans,” Brady told reporters last month.