A Republican-led committee of the Texas House of Representatives recommended on Thursday that the state’s attorney general, Ken Paxton, be impeached for a range of abuses of his office that the committee’s investigators said may have been crimes.

The recommendation thrust the State Capitol and its Republican leadership into uncharted political territory in the waning days of the legislative session, setting the stage for the House to hold a vote on impeachment, its first in decades and one of the few ever conducted in the state’s history.

If he is impeached, Mr. Paxton, a Republican who has been under a separate criminal indictment since 2015, would be required to step down from his post temporarily while he faces trial in the State Senate.

“There’s really no precedent — we’ve really only had two impeachments under the Constitution of 1876,” said Mark P. Jones, a professor of political science at Rice University. They include the governor in 1917, who resigned the day before the Senate convicted him, and a district judge who was convicted and removed in the 1970s.

Before the vote, the committee met in an executive session, outside public view.

“Overturning elections begins behind closed doors,” Mr. Paxton said in a post on Twitter that included video of a lawyer from his office arguing against impeachment to reporters in a nearly empty committee room, while the committee’s deliberations were underway.

After the vote, the committee filed 20 articles of impeachment against Mr. Paxton, charging him with a litany of abuses including taking bribes, disregarding his official duty, obstructing justice in a separate securities fraud case pending against him, making false statements on official documents and reports, and abusing the public trust.

Many of the charges related to the various ways that Mr. Paxton had used his office to benefit a particular donor, the committee said, and then fire those in the office who spoke up against his actions.

As the articles were being handed out around the House chamber late Thursday, Andrew Murr, the chairman of the committee, a Republican, said that they described “grave offenses” and that he intended to bring them up for a vote by the House.

The extraordinary developments were likely to test the Republican Party in Texas in new and unpredictable ways, at a time when divisions in the party have increasingly been exposed.

The Texas House is led by Speaker Dade Phelan, a Republican representing Beaumont who is seen as a traditional conservative. In contrast, Mr. Paxton has been allied with the most strident Republican legislators in Texas and with former President Donald J. Trump, in a camp that also includes the lieutenant governor and leader of the State Senate, Dan Patrick.

The House investigations committee, made up of three Republicans and two Democrats, voted unanimously to go forward with impeachment proceedings during a brief public session. “The chair moves that the committee adopt the articles of impeachment against Warren Kenneth Paxton, attorney general of the state of Texas,” Mr. Murr said.

It was not immediately clear when the House would take up the articles of impeachment and conduct a floor vote, though several members said they expected it would occur before the session ended on Monday. If not, lawmakers could call themselves back into a special session at any point to deliberate.

Asked by a House member about the timing of an impeachment vote, Mr. Phelan said on Thursday night that Mr. Murr would determine when to bring up the matter for a vote. He did not provide a timetable.

For much of Thursday, House members were preparing for what had already started to feel inevitable.

At least one lawmaker could be found researching the impeachment process in the Capitol’s library. “I’m trying to figure out what impeachment is all about,” said the lawmaker, Representative John Smithee, a Republican from the conservative Texas Panhandle. Speaking before the committee’s vote, he said that it was too early to cast judgment on the matter and that he believed officials might be rushing into impeachment.

“I would like to hear additional evidence instead of just a report,” Mr. Smithee said, “and his side of the story if he’s willing to tell it.”

The vote by the House committee came a day after hours of detailed testimony on Wednesday from a team of investigators — former prosecutors who were hired by the committee to look into corruption allegations against Mr. Paxton.

The investigators described how Mr. Paxton had abused and misused his office to help an Austin real estate developer and donor who also hired a woman with whom Mr. Paxton was having a relationship, and how Mr. Paxton had created a climate of fear within the office of the attorney general.

The misdeeds that Mr. Paxton was accused of committing rose to the level of possible criminality, the investigators said, including instances of retaliation against people who spoke up.

The committee did not take testimony during its session on Thursday.

The lawyer from Mr. Paxton’s office, Christopher Hilton, told reporters that the committee’s process had been “completely lacking” and called the testimony from Wednesday “false” and “misleading.” He added that the issues raised by the committee had been fully aired during Mr. Paxton’s re-election campaign last year, when he was elected to a third term.

“The 2022 election, the primary and the general was run on these issues, these allegations,” Mr. Hilton said. “The voters have spoken. They want Ken Paxton as their attorney general.”

And, in what appeared to be a preview of a possible legal challenge to the proceedings, Mr. Hilton said that Texas law allowed impeachment only for conduct since the preceding election.

Representative Trey Martinez Fischer, the chair of the Democratic caucus in the Texas House, said after the vote that impeachments were “very rare and very serious,” adding, “I trust that the committee has put a lot of work into it, and I will evaluate the evidence and see where this process takes us.”

Another Democrat, Representative Jon Rosenthal of Houston, said that the charges against Mr. Paxton were “pretty bad” and that he would very likely vote for impeachment. “I challenge you to find a Democrat who’ll say, ‘No, I won’t vote for impeachment,’” he said.

The investigation began in March, after Mr. Paxton, who is also under indictment for securities fraud, had apparently succeeded in putting at least one of his legal troubles behind him. He had agreed to a $3.3 million settlement with four of his top aides who had sued him, accusing him of corruption and retaliation.

Mr. Paxton had asked the Texas Legislature for the funds to pay the settlement. But Mr. Phelan, the House speaker, did not support that use of state money, and said he felt that Mr. Paxton had not sufficiently explained why the state should finance the settlement. The House investigation into the allegations was begun in order to gather information about the funding request, Mr. Phelan’s spokeswoman said.

For two days this week, as the committee’s investigation neared its conclusion, Mr. Paxton hurled accusations against Mr. Phelan, and claimed that the speaker presided over a House session last week while drunk. Mr. Paxton based his accusation on a video that circulated among hard-right activists who blame Mr. Phelan for the failure of various pieces of conservative legislation in the House.

Much of what was presented to the committee about Mr. Paxton was already known publicly from the allegations made in the aides’ lawsuit. The aides also took their complaints about Mr. Paxton to the F.B.I., which is still investigating.

The vote on Thursday rendered the first official judgment on those allegations, finding them sufficient to begin the process of removing Mr. Paxton from office.

The committee also voted to issue letters to the Texas Department of Public Safety and the Texas Facilities Commission, which manages state property, “to ensure that all evidence relevant to the committee’s inquiry” would not be “destroyed or concealed,” said Mr. Murr, the committee chairman.

The impeachment vote was the second time this year that the committee had recommended the removal of an elected official from office. The first involved a Republican state representative, Bryan Slaton; a committee investigation found that he had slept with a 19-year-old staff member after serving her alcohol.

Mr. Slaton resigned shortly after. The House then voted unanimously to formally expel him, and prevent him from holding office in the future.

David Montgomery contributed reporting.