House Ways and Means Committee chair Richard Neal (D-MA) formally requested six years of Donald Trump’s tax returns from the Internal Revenue Service Wednesday, setting up a likely legal fight with the administration over the request.

Trump is the first president in decades not to make his tax returns publicly available. The request could shed new light and answer longstanding questions about Trump’s finances.

Neal also requested the returns for eight of Trump’s business entities in a move that could provide yet more detail on the president’s financial history.

In making the request, Neal invoked an obscure Roaring Twenties-era provision that empowers the head of the ways and means committee – as well as two other congressional committees – to request the tax returns of any filer.

Neal wrote in the letter that he was demanding the returns within his duties to perform oversight of the executive branch, but the stated purpose of his request was rather limited. Neal is seeking the records not to investigate Trump wrongdoing, but rather how the IRS handles the review of presidential tax returns.

“Consistent with its authority, the Committee is considering legislative proposals and conducting oversight related to our Federal tax laws, including, but not limited to, the extent to which the IRS audits and enforces the Federal tax laws against a President,” Neal wrote in the letter.

House Dems are proposing a new law that would force all future presidential and vice presidential candidates to disclose at least 10 years of their personal tax returns as part of their marquee H.R. 1 legislation.

The request follows months of statements from Neal urging caution in the request, with the longtime Massachusetts legislator saying that lawmakers needed to be judicious in making the request.

“I am certain we are within our legitimate legislative, legal and oversight rights,” Neal said in a statement released on Wednesday.

The business returns that Neal is demanding are as follows:

The Donald J. Trump Revocable Trust

DJT Holdings LLC

DJT Holdings Managing Member LLC

DTTM Operations LLC

DTTM Operations Managing Member Corp.

LFB Acquisition Member Corp.

LFB Acquisition LLC

Trump National Golf Club – Bedminster

Tax experts told TPM in January that the business returns would likely provide a more detailed picture than the personal returns, which could serve as a roadmap for investigators.

Amid his statements urging caution, Neal had faced mounting pressure from the left and from party activists to act on the request, which had become a key talking point in the campaign for the 2018 midterms.

Rep. Bill Pascrell (D-NJ), a longtime Ways and Means Democrat, had issued repeated statements calling for Neal to make the request in the preceding months. Outside activists, expecting a lengthy court battle, had begun to worry that the request might not be fulfilled by the 2020 presidential election.

Read the letter here: