Bill Cassidy

Republicans who have tried to walk a careful line with President Donald Trump are having a rough stretch in primary season.

Louisiana Sen. Bill Cassidy and Texas Sen. John Cornyn both lost to Trump-backed challengers despite years of attempting, in different ways, to accommodate the president politically.

But accommodation is rarely enough with Trump. Republican senators hoping selective loyalty will protect them should pay attention to what happened to Cassidy and Cornyn: If Trump decides you are insufficiently loyal, you are replaceable no matter how often you vote with him.

Republican senators deciding whether and when to break with Trump should take that lesson seriously. The time to do it is when you still hold power, not once you’ve become a lame duck. The former requires courage. The latter does not.

It's easier to find principles once your political future is gone

Republicans who lose primaries to Trump-backed challengers often discover a new willingness to oppose him once the political consequences no longer matter.

One example is Cassidy, who visibly struggled with whether to support Robert F. Kennedy Jr.’s nomination as Health and Human Services secretary or break publicly with Trump.

Cassidy, a physician, understood the risks posed by Kennedy’s long record of vaccine skepticism. Yet he ultimately helped advance the nomination, casting a crucial vote to move Kennedy through the confirmation process.

I suspect Cassidy convinced himself that supporting Kennedy was the politically responsible choice. If he voted no, he likely understood, Trump would replace him with someone even more loyal and less serious.

But that calculation failed. Cassidy learned the same lesson Cornyn did: With Trump, partial loyalty is rarely enough. Once the president decides you are insufficiently committed to him personally, attempts at accommodation buy little protection.

Now free from the immediate political consequences, Cassidy has shown a greater willingness to break with the administration, including on military action in Iran. He joined Democrats and a small group of Republicans in opposing further escalation after previously supporting the administration’s initial response.

Republicans willing to break with Trump are still notable in today’s GOP. But opponents of the president should not confuse post-defeat independence with political courage. It is easier to oppose a president after he has already ended your career than when your vote might still carry real consequences.

Principles matter most when they carry consequences

I suspect that, given the chance to do it over again, Cassidy would vote differently on Kennedy’s nomination now that his political future is no longer hanging in the balance.

But that is exactly why moments like those matter. Political principles are only meaningful when exercising them carries a real cost.

If Cassidy truly wanted to shape the course of the administration, the moment to do it was when Kennedy’s nomination sat before the Senate. Supporting the nomination did not save the senator's seat, earn lasting favor with Trump or moderate the direction of the administration. It simply helped install one of the administration’s most controversial Cabinet picks.

Cornyn offers another example. Despite his reputation as a more traditional and institution-minded conservative, the senator spent much of his reelection campaign trying to demonstrate his loyalty to Trump rather than making an affirmative case for himself.

It did not matter. Trump ultimately endorsed Texas Attorney General Ken Paxton, a candidate facing serious ethical and character concerns, and Paxton cruised to victory largely on the strength of that endorsement.

Republicans should learn from what happened to both Cornyn and Cassidy. Attempting to carefully manage a relationship with Trump offers little security if he concludes you are not personally loyal enough. And once your political career is already ending, acts of independence carry much less weight.

If Republican senators truly disagree with the direction of the party or the administration, the time to say so is while their votes and influence still matter. Anything else risks becoming an empty gesture.

Dace Potas is an opinion columnist for USA TODAY and a graduate of DePaul University with a degree in political science.