Attorney General Ken Paxton has spent much of his career, which has taken him to the heights of Republican politics, trailed by a raft of criminal and civil accusations.

But in the final days of the Biden administration, The Associated Press reported Thursday, the Justice Department defused the most serious legal threat he faced — a federal criminal probe into allegations of corruption — by declining to prosecute and effectively ending the investigation.

With the investigation over, Paxton has nearly cleared his crowded slate of career-threatening legal battles, just as he gears up for a likely 2026 primary run against U.S. Sen. John Cornyn.

“The end of this investigation is both politically and personally a huge boon for Ken Paxton,” said Matthew Wilson, a political science professor at Southern Methodist University. “Paxton can point to that and say, ‘You see, even under a Democratic administration, they didn’t feel that there was anything there that merited moving forward.’”

Two sources familiar with the issue, who spoke on the condition of anonymity to discuss internal deliberations, told the AP of the Justice Department’s decision, including that it was made while President Joe Biden was still in office. The DOJ did not immediately respond to questions about confirming the AP report.

The development extends a multiyear string of legal victories vindicating the once-embattled Republican. It underscores Paxton’s durability through all manner of political, personal and legal troubles and helps burnish his reputation among the right wing of his party as a fighter who, like President Donald Trump, has defied numerous efforts by his detractors to take him down.

“It really sets up those parallels to Trump that will play very well among the Republican primary electorate,” Wilson said. “Paxton is a political survivor. People have written his obituary a couple of times, and he has really forged this loyal base among the grassroots activists in the Republican Party.”

Paxton’s attorney Dan Cogdell said he learned of the outcome from the AP because the Justice Department never notified him of its decision not to prosecute.

“The fact that they declined prosecution is not a surprise,” Cogdell said. “I don’t really think they ever had a case to begin with.”

There was little concern that the case would continue under the Trump administration’s Justice Department, given Paxton’s close alliance with the president.

In January, the Texas Supreme Court tossed the State Bar of Texas’ lawsuit against Paxton over his efforts to overturn the results of the 2020 election won by Biden.

Prosecutors last year dropped felony securities fraud charges against Paxton just three weeks before he was set to face trial, after he agreed to perform 100 hours of community service, take 15 hours of legal ethics courses and pay $271,000 in restitution to those he was accused of defrauding more than a decade ago. The deal ended a nearly nine-year-old felony case that had dogged Paxton since his early days in office.

And when the state Legislature sought to impeach him for the same allegations of corruption that spurred the federal investigation, the Texas Senate acquitted him of 16 charges of bribery, abuse of office and obstruction – charges that more than 70% of his own party had supported in the House.

Paxton’s last outstanding legal battle is a whistleblower lawsuit filed against him by four of the former senior aides who reported him to the FBI, who allege that he fired them improperly after they spoke out. The Texas Supreme Court said in November that Paxton would not have to sit for a deposition in the lawsuit — another win for the attorney general, who has managed to avoid testifying about the corruption allegations through the civil lawsuit, his impeachment trial and the federal investigation. Paxton last year said he would no longer contest the facts of the case in order to end what he called “wasteful litigation” and a distraction for his office.

The whistleblowers are now waiting on a Travis County district judge to rule on a settlement.

“DOJ clearly let political cowardice impact its decision. The whistleblowers — all strong conservatives — did the right thing and continue to stand by their allegations of Paxton’s criminal conduct,” TJ Turner and Tom Nesbitt, attorneys for some of the whistleblowers, told the AP in a statement.

On Thursday, Paxton referenced the end of the federal investigation to take a swing at Cornyn, who has been critical of Paxton’s legal controversies and steadfast in his bid for reelection.

“This former TX Supreme Court Justice and TX Attorney General ignored the rule of law, the Constitution, and innocent until proven guilty while standing with the corrupt Biden DOJ cheering on the bogus witch hunts against both me and President Trump,” Paxton posted on social media in reference to Cornyn, adding, “Care to comment now, John?”

In response to an attempt by Paxton to tag Cornyn as insufficiently conservative and supportive of Trump, Cornyn had said, “Hard to run from prison, Ken.”

The likely matchup could prove to be Cornyn’s toughest primary battle yet as Texas Republican primary voters lurch toward the right and his popularity among GOP voters drops from 2020 highs.

Among Republican-identifying voters, according to polling by the Texas Politics Project at the University of Texas at Austin, Cornyn has a 49% approval rating, compared to Paxton’s 62% approval rating. Texas’ other senator, Ted Cruz, meanwhile, has an approval rating of 78% among Republicans.

Still, Cornyn, who has trounced past challengers, is a prodigious fundraiser and wields widespread influence as a senior senator. He has also worked to smooth over his relationship with the hard-right in Texas and tout his work in the Senate in support of Trump.

On Thursday, Cornyn declined to comment on Paxton or the Justice Department decision not to prosecute, saying he was “not going to have any comments about that until he’s an announced candidate. Then I’ll have a lot to say.”

In response to a request for comment, Cornyn’s campaign, meanwhile, sent an endorsement from the National Border Patrol Council that was announced Thursday.

Cruz declined to comment.

“Fundamentally, he’s a fighter, and he’s also a risk-taker,” said Matt Mackowiak, a Republican strategist and the former Travis County GOP chair, describing Paxton’s position heading into a potential campaign with the federal investigation behind him. “What I think this whole episode taught him is, trust your instincts and never quit. The psychology of that has to be very powerful for him in approaching this race.”