AUSTIN, Texas (AP) — The Texas Senate is set to gavel in Tuesday for the impeachment trial of Attorney General Ken Paxton, a political reckoning of years of alleged corruption that could lead to his permanent ouster from office.

The fate of Paxton, a 60-year-old Republican, is in the hands of GOP senators with whom he served before winning a statewide race to take charge of the attorney general’s office in 2015.

In an era of bitter partisanship, the historic proceeding is a rare instance of a political party seeking to hold one of its own to account for allegations of wrongdoing. The impeachment also came as a sudden rebuke to Paxton, who has built a national profile fighting high-profile legal battles, including trying to overturn the 2020 presidential election, and who won a third term in 2022 despite long-pending state criminal charges and an FBI investigation.

The Republican-led House of Representatives voted overwhelmingly to impeach Paxton in May, largely based on his former deputies’ claims that the attorney general used his power to help a wealthy donor who reciprocated with favors including hiring a woman with whom Paxton had an extramarital affair. The 20 articles of impeachment include abuse of public trust, unfitness for office and bribery.

The 121-23 vote immediately suspended Paxton and made him only the third sitting official in Texas’ nearly 200-year history to be impeached.

Paxton has decried the impeachment as a “politically motivated sham” and an effort to disenfranchise his voters. The attorney general’s lawyers say he won’t testify in the Senate trial. He has said he expects to be acquitted.

Paxton faces trial by a jury — the 31 state senators — stacked with his ideological allies and a “judge,” Republican Lt. Gov. Dan Patrick, who loaned $125,000 to his last reelection campaign. His wife, Sen. Angela Paxton, will attend the trial but cannot participate or vote. Two other senators play a role in the allegations against Paxton.

A two-thirds majority — or 21 senators — is required for conviction, meaning that if all 12 Senate Democrats vote against Paxton, they still need at least nine of the 19 Republicans to join them.

The trial will likely bring forth new evidence. But the outline of the allegations against Paxton has been public since 2020, when eight of his top deputies told the FBI that the attorney general was breaking the law to help Austin real estate developer Nate Paul.

The deputies — largely conservatives whom Paxton handpicked for their jobs — told investigators that Paxton had gone against their advice and hired an outside lawyer to probe Paul’s allegations of wrongdoing by the FBI in its investigation of the developer. They also said Paxton pressured his staff to take other actions that helped Paul.

In return, Paul allegedly hired a former aide to a Republican state senator with whom Paxton was having an affair and bankrolled the renovations of one of the attorney general’s properties, a million-dollar home in Austin.

Paul was indicted in June on federal criminal charges that he made false statements to banks to secure more than $170 million in loans. He pleaded not guilty and has broadly denied wrongdoing in his dealings with Paxton.

The two men bonded over a shared feeling that they were the targets of corrupt law enforcement, according to a memo by one of the staffers who went to the FBI. Paxton was indicted on securities fraud charges in 2015 but is yet to stand trial. The Senate is not taking up, at least initially, three impeachment articles about the alleged securities fraud and a fourth related to Paxton’s ethics filings.

Federal prosecutors continue to examine Paul and Paxton’s relationship, so the evidence presented during his impeachment trial poses a legal as well as a political risk to the attorney general.

After going to the FBI, all eight of Paxton’s deputies quit or were fired. Their departures led to an exodus of other seasoned lawyers and saw the attorney general’s office consumed by dysfunction behind the scenes.

Four of the deputies later sued Paxton under the state whistleblower act. The bipartisan group of lawmakers who led Paxton’s impeachment in the House said it was him seeking $3.3 million in taxpayer funds to settle with the group that prompted them to investigate his dealings.