Deliberations began on Friday in the impeachment trial of Ken Paxton, the Texas attorney general, as the jury of state senators weighed allegations of bribery and abuse of office based on complaints made against him by his most senior former aides.

Before deliberating, the senators — 19 Republicans and 12 Democrats — heard closing arguments from the House impeachment managers, led by Republican lawmakers who oversaw the prosecution, and from Mr. Paxton’s lawyers.

“The defense isn’t that he didn’t do it, it’s that it doesn’t matter because he won the election,” Representative Andrew Murr, a West Texas Republican who led the impeachment managers, said in his closing argument. “That is a godless, rudderless morality, and it cannot be the new normal in Texas.”

Mr. Paxton sat listening at the defense table, the first time he has appeared in the Senate chamber for the trial since he entered a plea of not guilty on opening day. From the spectators’ gallery above Mr. Paxton, at least three of his former senior aides who testified at the trial sat together, looking down on the proceedings.

The closing arguments came on the ninth day of a trial that has gripped the Texas Capitol and pitted two factions of an increasingly divided Republican Party against each other over the fate of an attorney general seen by many voters in the state as their conservative champion.

Only twice before in the state’s history have Texas senators been asked to consider expelling an elected official from office, and not since 1917 have they done so for a statewide official. Both previous impeachment trials ended in conviction.

In defense of Mr. Paxton, his lead lawyer, Tony Buzbee, argued that the prosecution — which he referred to at points as being brought by “these people” — had failed to prove the allegations beyond a reasonable doubt, the standard for the Senate trial. His voice echoing through the towering chamber, Mr. Buzbee attacked the case as “a joke” and “a political witch hunt” that had been motivated by rivalries and animosity among Republicans.

“This trial has displayed, for the country to see, a partisan fight within the Republican Party,” Mr. Buzbee said. “It’s a battle for power.”

Supporters of Mr. Paxton, who closely aligned himself with former President Donald J. Trump, have sought from the start to portray the trial as a plot by more moderate Republicans to undermine the party’s ascendant conservative wing. The Republicans who backed his impeachment, including a majority of those in the Texas House, have said that Mr. Paxton has to be held to account for his actions, regardless of party.

“Let’s be very clear: None of us want to be here today,” Representative Jeff Leach, a Dallas-area Republican and member of the House board of managers, said in his closing argument. Mr. Leach said he had “loved Ken Paxton for a long time,” calling him a “brother in Christ” and describing how he had supported him.

“Which is one of the reasons this is so difficult for me,” Mr. Leach said of his role in Mr. Paxton’s impeachment. He urged the senators “not to ask what is safe, or popular, or politic, but what is right.”

A two-thirds vote to convict on any of the 16 articles of impeachment considered during the trial would immediately remove Mr. Paxton from office. A subsequent vote would then take place to determine whether to permanently bar him from holding any future office. Mr. Paxton has been suspended as attorney general since May, when the Republican-controlled Texas House voted to impeach him in a 121-to-23 vote.

No timetable was set for the closed-door deliberations by the senators. But Lt. Gov. Dan Patrick, who presides over the Senate and acted as a judge in the impeachment trial, set forth rules including that senators could not communicate with their staff or bring cellphones in to the deliberation room. He said they would deliberate until 8 p.m. on Friday and, if they had not finished before then, would return on Saturday at 9 a.m.

The prosecution, in its closing argument, sought to direct the senators to key moments in the trial where they said the case against Mr. Paxton had been proven. They showed clips of witnesses’ testimony and highlighted exhibits that they urged the senators to look at during deliberations.

Mr. Buzbee also used visual aids to highlight his case. At one point, he called the prosecution’s case “hogwash” and showed a cartoon of a pig in a bath. At another, he said Mr. Paxton’s aides had made assumptions without evidence and referred to a crude saying about people who assume things. As he did so, a cartoon of a donkey, seen from behind, appeared on the screen.

“I am proud to represent Attorney General Ken Paxton. If this can happen to him, it can happen to anyone,” Mr. Buzbee said.

The case is based on a range of actions that prosecutors said Mr. Paxton took to benefit an Austin real estate investor, friend and donor named Nate Paul. The prosecution’s witnesses testified that Mr. Paxton involved himself in seemingly minor legal matters involving Mr. Paul in 2020. That included intervening in a lawsuit between Mr. Paul and a nonprofit, creating legal guidance to stop foreclosure sales at a time when Mr. Paul had properties facing foreclosure, and crafting a legal ruling to assist Mr. Paul in getting information related to a law enforcement search of his home and business.

Mr. Paxton also used the attorney general’s office to hire an outside lawyer to investigate claims made by Mr. Paul — over the objections of his director of law enforcement — that there had been a conspiracy among state and federal law enforcement officials to doctor the search warrant. The lawyer issued grand jury subpoenas, an action that Mr. Murr said he had no authority to do.

Mr. Paul, who was indicted in June on federal fraud charges, did not testify during the trial.

In exchange for actions by his office, the prosecutors said, Mr. Paxton received “tangible benefits” from Mr. Paul.

“What we know is that Nate Paul gave Mr. Paxton’s mistress a job, so that she could move from San Antonio to Austin, and be closer,” Mr. Murr said, “provided free Uber rides to her apartment and Nate Paul provided renovations, free renovations, to Mr. Paxton’s Austin home until he was caught.”