WASHINGTON — The House committee investigating the Jan. 6 attack on the Capitol issued subpoenas on Thursday to five Republican members of Congress, including Representative Kevin McCarthy, the minority leader, who had refused to meet with the panel voluntarily.
The committee’s leaders had been reluctant to issue subpoenas to their fellow lawmakers. That is an extraordinarily rare step for most congressional committees to take, though the House Ethics Committee, which is responsible for investigating allegations of misconduct by members, is known to do so.
All five have refused requests for voluntary interviews about the roles they played in the buildup to the attack by supporters of the former president who believed his lie of widespread election fraud.
The subpoenas come as the committee is ramping up for a series of public hearings in June to reveal its findings. The eight hearings are slated to take place over several weeks beginning June 9, some during prime time in an effort to attract a large television audience.
“The select committee has learned that several of our colleagues have information relevant to our investigation into the attack on Jan. 6 and the events leading up to it,” Representative Bennie Thompson, Democrat of Mississippi and chairman of the committee, said in a statement. “Before we hold our hearings next month, we wished to provide members the opportunity to discuss these matters with the committee voluntarily. Regrettably, the individuals receiving subpoenas today have refused and we’re forced to take this step to help ensure the committee uncovers facts concerning Jan. 6.”
For weeks, members and investigators on the special House panel have privately agonized over how aggressively to pursue sitting members of Congress, weighing their desire for information about lawmakers’ direct interactions with Mr. Trump against the potential legal difficulty and political consequences of doing so.
Behind closed doors, committee and staff members researched the law, parliamentary rules and past precedents before coming to a decision to proceed, people familiar with the inquiry said.
In letters to the lawmakers sent Thursday, Mr. Thompson wrote that their refusal to cooperate had left the panel with “no choice” but to issue subpoenas.
The subpoena to Mr. McCarthy is particularly noteworthy because he is in line to become speaker if Republicans win control of the House this November. Should he refuse to comply, it could set in motion a process that could lead to a Democratic-controlled House holding him in contempt of Congress as the midterm elections loom.
Congressional investigators have rarely confronted a situation that carries such hefty stakes for their institution.
Mr. McCarthy has long feared being subpoenaed in the investigation. In recent months, he has been in discussions with William A. Burck, a longtime Washington lawyer, about how to fight a subpoena.
Mr. McCarthy issued a blistering statement in January condemning the committee as illegitimate and saying he would refuse to cooperate with its inquiry. He has argued that the panel was violating the privacy of Republicans through subpoenas for bank and phone records. Mr. McCarthy also denounced Speaker Nancy Pelosi of California for having rejected two of his five choices to sit on the panel — one of whom was Mr. Jordan.
The committee informed Mr. Jordan in December by letter that its investigators wanted to question him about his communications related to the run-up to the Capitol riot. Those include Mr. Jordan’s messages with Mr. Trump and his legal team as well as others involved in planning rallies on Jan. 6 and congressional objections to certifying Joseph R. Biden Jr.’s victory.
In a letter to Mr. Biggs, the committee’s leaders wrote that they wanted to question him about evidence they had obtained on efforts by certain House Republicans to seek a presidential pardon after Jan. 6 in connection with Mr. Trump’s efforts to overturn the 2020 election.
And the panel said it wants to question Mr. Brooks about statements he made in March claiming that Mr. Trump had asked him repeatedly in the months since the election to illegally “rescind” the results, remove President Biden and force a special election.
The so-called speech or debate clause of the Constitution, intended to protect the independence of the legislative branch, says that senators and representatives “shall not be questioned in any other place” about any speech or debate in either chamber, and has been broadly interpreted to cover all legislative actions, not just words. On its face, however, that clause is limited to questioning them in “other” places, like courtrooms.
There is also precedent for the House to subpoena its own members in a narrow context. The House Ethics Committee, which is responsible for investigating allegations of misconduct by members, has authority under the chamber’s rules to subpoena members for testimony or documents, and members are required to comply.
The committee has also sought an interview with Representative Ronny Jackson of Texas, Mr. Trump’s former White House doctor, about why he was mentioned in encrypted messages from the Oath Keepers, a militia group, some of whose members have been charged criminally in connection with the attack.
Mr. Jackson also has refused to voluntarily cooperate, but he was not among those issued a subpoena Thursday.