WASHINGTON — Fearing an embarrassing spectacle — or a defeat — eight weeks before Election Day, House conservatives and the leaders of the House Judiciary Committee agreed to call off a vote Thursday to impeach the Internal Revenue Service commissioner in exchange for formal impeachment hearings next week before the committee.

The last-minute deal struck Wednesday night may merely postpone the unprecedented step of formally accusing John A. Koskinen, 77, the head of the IRS, of “high crimes and misdemeanors.’’ Never before has an executive branch official below the Cabinet rank been impeached, and not even a Cabinet member has faced such proceedings in 140 years.

But Republican leaders in the House and Senate had made it clear they did not want such a distraction before the election.

Under the deal, the Judiciary Committee will convene official hearings next Wednesday and allow Koskinen to defend himself under oath, traditionally the next steps in the impeachment process.

Koskinen has signaled that he will cooperate with the proceedings. In a letter to top members of the committee last week, his lawyers wrote that Koskinen “has been and is willing to participate in this committee’s traditional process for investigating the potential impeachment of executive branch officials,’’ including testifying under oath.

The accusations against Koskinen stem from revelations in 2013 that IRS officials had singled out a number of organizations — hundreds of them Tea Party-affiliated groups — for additional scrutiny before granting them tax-exempt status.

The agency apologized, and a Justice Department investigation ultimately uncovered evidence of “poor judgment,’’ among other systemic problems, but not criminal activity. But Koskinen was not in government at that time. He became the nation’s top tax collector at the end of 2013.

Some Republicans say Koskinen lied to Congress in 2014 when he promised to turn over e-mails sent and received by a senior IRS official when some groups were applying for tax-exempt status.

New York Times