Mastriano was first subpoenaed by investigators on the January 6 probe in February. He cooperated in part, handing over some records related to the charter buses he organized, including physical receipts that showed his campaign helped sell 130 tickets to the ‘Stop the Steal’ protest at the Ellipse.

But the majority of what Mastriano produced was already information on the public record, and in a series of files Parlatore made available this May, document after document features Mastriano promoting Trump’s election fraud conspiracy theories or calling for a delay to the Joint Session on January 6.

In the letter, Parlatore argues that the committee does not have the authority to compel testimony because its membership was improperly composed from the start. Parlatore argues that the committee’s founding resolution requires that a ranking member is appointed by the party in the minority.

House GOP leader Kevin McCarthy had multiple opportunities to appoint his picks, but when his initial rounds were rejected, he ended his participation altogether.

But this dynamic, according to Parlatore, was what led the committee to take testimony from Bernie Kerik voluntarily instead of forcing him to speak by way of subpoena. Kerik, a former New York City Police Department commissioner, was present for several key meetings where Trump’s fake elector bid was plotted. He was also part of multiple meetings at Trump’s “war room” at the Willard Hotel. Kerik is also represented by Parlatore.

Notably, Mastriano’s lawyer steered clear of other legal arguments that have been attempted before by opponents of the January 6 investigation. Those who have argued that the select committee lacks constitutionality or standing have been shut out time and again. This was already put to the test by Trump’s lapdog and former strategist Steve Bannon, as well as Trump’s former trade adviser, Peter Navarro.

Bannon was found guilty of criminal contempt of Congress and awaits sentencing. Navarro has been indicted on contempt of Congress charges and now awaits trial.

When Trump tried to shield his presidential records from the committee after Biden waived executive privilege, his attack on the committee’s viability also failed.

When John Eastman, the attorney who penned a six-point strategy for Trump to overturn the 2020 election, was subpoenaed by the committee, he too argued it lacked authority. But he lost that bid and his emails have become one of the most integral discoveries to emerge from the select committee’s investigation.

A federal judge, upon reviewing them, said last year that it appeared Trump and Eastman were likely plotting a criminal conspiracy to overturn the election and were engaged in a “coup in search of legal theory.”

Mastriano is insistent that he has “nothing to hide,” but the committee has historically suggested that the Republican was part of efforts to place Trump’s fake electors in Pennsylvania.

If the select committee wants to wage a battle in court with Mastriano, Parlatore said his client is willing.

I have proposed what I believe to be a reasonable arrangement that will assuage my client’s concerns while also providing you with immediate access to the non-privileged information that you seek,” he wrote.

If a “reasonable” agreement can’t be reached, he added, then there will be “little choice but to go to court and litigate the issue.”

A committee spokesperson did not immediately return a request for comment Friday.