WASHINGTON — For decades, Sen. John Cornyn operated as a disciplined Republican insider, rising through the Senate while carefully navigating the party’s shifting centers of power.

Then Donald Trump helped destroy his political future.

Now, with his career approaching its end and the threat of another Republican primary finally gone, the Texas senator appears ready to use his remaining months in Washington against the president who abandoned him.

“You ain’t seen nothing yet,” Cornyn warned, according to Punchbowl News.

The words landed like a promise—and a threat.

Cornyn lost May’s Republican runoff to Texas Attorney General Ken Paxton after Trump endorsed Paxton as a “true MAGA warrior.” The president accused Cornyn of disloyalty and helped deliver a crushing defeat to the four-term incumbent.

Associated Press reporting described Cornyn as the first Republican senator from Texas to lose his party’s nomination for reelection. Paxton defeated him by more than 25 percentage points, abruptly ending a Senate career that began in 2002.

Cornyn initially promised to support the Republican ticket in November.

But supporting his party’s nominee does not mean surrendering his remaining influence to Trump.

Cornyn still possesses something the White House desperately needs: a vote on the Senate Judiciary Committee, where Acting Attorney General Todd Blanche’s nomination to permanently lead the Justice Department faces intense scrutiny.

At the center of the confrontation is the administration’s proposed “anti-weaponization” fund.

The controversial arrangement called for nearly $1.8 billion to compensate people claiming they had been unfairly targeted by the Justice Department during the Biden administration. Critics from both parties questioned its size, purpose and potential for political favoritism.

Blanche has repeatedly insisted that the fund is dead.

“The weaponization fund is dead,” he told senators during his confirmation hearing.

But Cornyn is not satisfied with a verbal assurance. He has pressed the administration to formally eliminate the language that could allow the proposal to return.

CBS News reported that the settlement documents had not yet been amended, even after Blanche declared that the Justice Department would not create the fund.

That unresolved detail gives Cornyn leverage.

“They’re not enthusiastic about it,” he said of the White House. “But if they want to get [Blanche] out of the committee, I think they realize they need to talk to us.”

The message was unmistakable: officially kill the fund, or risk seeing the attorney general nomination stall.

Cornyn has already demonstrated that he is willing to use Trump’s nominees as bargaining chips.

Last week, he threatened to block two ambassadorial nominees—Kari Lake for Jamaica and Doug Mastriano for Slovakia—unless the administration released $1.3 billion in congressionally approved funding for the President’s Emergency Plan for AIDS Relief.

The global health program, launched under President George W. Bush, has long enjoyed bipartisan support. Cornyn argued that holding the nominees was necessary to force the White House to honor funding approved by Congress.

The administration ultimately offered a commitment, giving Cornyn an early victory in what he described as his period of “newfound political freedom.”

That freedom could become a recurring nightmare for Trump.

Throughout his second term, the president has used endorsements and primary challenges to punish Republican lawmakers viewed as insufficiently loyal. The strategy has removed several incumbents—but it has also created a group of outgoing legislators with little incentive to obey him.

Cornyn is not alone.

Rep. Thomas Massie and Sens. Thom Tillis and Bill Cassidy have also been defeated or pushed aside by Trump-backed challengers. Each retains voting power until leaving office. Each knows that cooperation cannot save a political career already ended by the MAGA movement.

They are not necessarily forming an organized anti-Trump coalition, and they continue to support many Republican policies. But on close votes, even a handful of angry departing lawmakers could delay nominees, demand policy concessions or disrupt the president’s legislative agenda.

Trump’s method once relied on fear: Defy him, and he might end your career.

Cornyn’s defeat has removed that weapon.

The president helped turn a loyal Republican senator into a man with nothing left to lose—and several months remaining to settle unfinished business.

The White House may soon discover that removing an opponent from the next ballot does not remove him from power today.