A group of House conservatives is making a last-ditch effort to force a floor vote to impeach Internal Revenue Service Commissioner John Koskinen because of their continuing frustrations over how the agency has treated small-government groups.

House Freedom Caucus members John Fleming (R-La.) and Tim Huelskamp (R-Kan.) on Thursday employed a rarely used procedural maneuver that allows any member to have an issue considered by the full House.

The move means that any action would probably happen shortly after lawmakers return in September following a seven-week recess.

“Congress has held countless congressional hearings on the impeachable offenses of Koskinen — but there have been zero consequences for his behavior,” Huelskamp said in a news release. “It is time for him to be impeached and removed.”

The lawmaker said a vote is “necessary to bring national attention to this disgrace and to impeach and remove at least one Obama Administration official.”

House conservatives, led by the approximately 40-member House Freedom Caucus, want to oust Koskinen as retaliation for the IRS’s treatment of conservative groups, which were subjected to extra scrutiny in a high-profile misstep revealed by the agency’s watchdog in 2013.

Koskinen, with a long private-sector career, came out of retirement to turn around the IRS after the scandal. But he has been dogged by allegations from Republicans that he blocked their investigation, lied under oath about lost email communications and flouted a congressional subpoena.

The Treasury Department, the IRS’s parent agency, has called the charges baseless.

The last time Congress brought similar articles of impeachment was in 1876, after the House uncovered evidence of a pattern of corruption by War Secretary William Belknap. No lower-level executive-branch officials have been impeached.

House Speaker Paul D. Ryan (R-Wis.) has resisted holding a vote to impeach Koskinen, but the move by Fleming and Huelskamp will force him to deal with the issue in September.

Asked Thursday at a news conference whether the issue has put him at odds with conservatives in his party, Ryan responded, “This is something we haven’t been focused on.” He said he has been busy with other legislation, such as passing a measure to combat opioid addiction and considering annual spending bills.

“When we return from our work period we will talk about it as a family,” he said.

The Justice Department formally closed its investigation of the scandal last fall without filing criminal charges. But conservatives continued to press their case, urging Ryan to allow impeachment hearings in the Judiciary Committee.

The House Oversight and Government Reform Committee held two hearings on the matter this spring but has not voted on impeachment. It did vote along party lines, however, to recommend censuring Koskinen, a far less severe punishment.

The IRS said Thursday that history is on Koskinen’s side.

“Commissioner Koskinen believes that a traditional, fair impeachment process that follows historical precedent would demonstrate that neither impeachment nor censure is warranted,” the agency said in a statement. “If this proceeds, he deserves an opportunity to refute the allegations and fully respond to these charges before a House vote on the allegations. The Commissioner has made it clear that he testified truthfully and that the facts clearly do not support the claims.”

Correction: An earlier version of this post said the Judiciary Committee held hearings and voted to censure Koskinen. In fact, the Oversight Committee held the hearings and voted to recommend censure.