Kevin McCarthy, the top Republican in the House, indicated on Friday to the House select committee investigating the Capitol attack that he would not cooperate with a subpoena unless he could review deposition topics and the legal rationale justifying the request.

The California congressman’s response adopts an adversarial position similar to other subpoenaed Republican Congress members, and it sets a conundrum for the panel over whether to entertain the requests that also challenge the January 6 inquiry’s legitimacy.

McCarthy appeared to tell the select committee in an 11-page letter through his lawyer that he would not consider complying with the subpoena until House investigators turned over materials that would reveal what the panel intended to use in questioning ahead of a deposition.

The House minority leader also asked the panel to give him internal analyses about the constitutional and legal rationales justifying the subpoena, and whether the panel would adhere to one-hour questioning between majority and minority counsel, according to the letter.

McCarthy’s references to the minority counsel amounted to a thinly veiled attack at the investigation, which Republicans have called illegitimate because the House speaker, Nancy Pelosi, refused last year to appoint some of McCarthy’s picks for the Republican minority.

The accusations, however, are to some degree disingenuous: it was McCarthy who pulled all Republican participation, incensed at Pelosi’s refusals, rather than name different members. Pelosi later added Republican congressmembers Liz Cheney and Adam Kinzinger to the panel.

McCarthy’s requests also appeared phrased in a manner expecting the select committee to decline his requests, with the letter accusing the panel of issuing unprecedented subpoenas to five House Republicans in an illegal and unconstitutional manner.

“The select committee is clearly not acting within the confines of any legislative purpose,” the letter said. “It is unclear how the select committee believes it is operating within the bounds of law or even within the confines of any legislative purpose.”

The response from McCarthy largely mirrored the response from Ohio congressman Jim Jordan on Wednesday. In the letter, obtained by the Guardian, Jordan said he would consider complying only if the panel shared material that put him under scrutiny.

Like with Jordan, it was not immediately clear how McCarthy might act if the select committee refused his requests. The investigation’s standard operating procedure to date has been not to share such materials with witnesses, according to a source familiar with the matter.

The panel’s next move could have significant ramifications for both its inquiry and Congress. If the panel refused the request and the five subpoenaed House Republicans in turn declined to cooperate, it could leave large unanswered questions about the Capitol attack.

But it could also set a problematic precedent for Republicans themselves, who might like the idea of subpoenaing Democrats in partisan investigations should the GOP take control of the House – as Capitol Hill widely expects – after the 2022 midterm elections.

A spokesperson for the select committee declined to comment.

The resistance from McCarthy came as he and Jordan denounced the investigation as a “kangaroo court” in a Wall Street Journal op-ed. “For House Republican leaders to agree to participate in this political stunt would change the House forever,” they wrote.

With McCarthy’s refusal to appear for a deposition without first receiving materials from the select committee, at least four of the five Republicans subpoenaed to testify about their roles in the events of 6 January have now declined to comply without some sort of negotiation.

The current chairman of the ultra-conservative House Freedom Caucus, Scott Perry, and its previous chairman, Andy Biggs, have both sent letters to the panel refusing to cooperate, CNN reported. It was not clear whether the fifth Republican, Mo Brooks, would comply.