Congressional Republicans denied any similarity between the two episodes, pointing out that Nixon requested the investigation into his returns while Trump has not.

On Dec. 13, 1973, Laurence N. Woodworth of the Joint Committee on Taxation asked the IRS commissioner to review Nixon’s tax returns from 1969 through 1972, according to the documents. Nixon had asked the congressional committee to review the documents amid the widening Watergate scandal.

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In a letter to the committee also dated Dec. 13, 1973, IRS Commissioner Donald C. Alexander said that enclosed in his response were attachments of “true copies of the original joint federal income tax returns filed by Richard M. and Patricia R. Nixon” for the years requested.

House Ways and Means Committee Chair Richard E. Neal (D-Mass.) has requested six years of Trump’s personal and business tax returns, from 2013 to 2018, a period that includes several years before Trump became president.

Neal recently sued the Trump administration in federal court to obtain the records, after Treasury Secretary Steven Mnuchin argued in a May letter that Neal’s “unprecedented request” should be denied.

The Ways and Means Committee voted in executive session to make the documents public. In a memo sent Thursday to other members of the committee, Neal said the letters confirm his interpretation of U.S. Code Section 6103, which pertains to congressional requests for private taxpayer information.

“Section 6103 has been used to obtain the tax returns and return information of a sitting President,” Neal said in the letter. “Where records were available, the IRS complied with JCT’s requests without delay or objection.”

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An IRS spokesman did not immediately return a request for comment. Congressional Republicans immediately slammed “unprecedented Democrat overreach” in releasing the documents, also arguing they were not similar to the fight over Trump’s returns. GOP lawmakers also noted that, unlike Trump, Nixon voluntarily requested that the JCT look into his tax returns.

“This is a travesty,” Rep. Kevin Brady (Tex.), the ranking Republican on the Ways and Means Committee, said in a statement. “[The documents] shed no light and have no comparison to Democrats’ illegitimate and unprecedented request.”

But Joe Thorndike, a historian and policy analyst for Tax Notes, said the documents undermine one argument Mnuchin has made for denying the request for the documents. A Joint Committee on Taxation memo that had already been made public suggested the committee had reviewed Nixon’s taxes, but the new letters erase any doubt, Thorndike said.