The looming debt ceiling vote is the perfect hook. The increase in the annual deficit under Trump ranks as the third-largest increase, relative to the size of the economy, of any U.S. presidential administration. Long before Covid, Republicans in Congress were told by the Trump White House to spend more — and that spending contributed to the current debt crisis. Mr. Trump will say he was fiscally responsible, but the actual numbers don’t lie. “We can’t afford these deficits. We can’t afford this debt. We can’t afford Donald Trump.”

Sixth, there’s one character trait that unites just about everyone: an aversion to public piety while displaying private dishonesty. In a word, hypocrisy. Until now, that hasn’t worked for Trump’s opponents, but that’s because the examples weren’t personally relevant to Mr. Trump’s voters. During his 2016 campaign, Trump condemned Barack Obama repeatedly for his occasional rounds of golf, promising not to travel at taxpayer expense. What was Trump’s record? Close to 300 rounds of golf on his own personal courses in just four years, costing hardworking taxpayers roughly $150 million in additional security. This may sound minor, but delivered on the debate stage, it could be lethal. “While more than half of America was working paycheck to paycheck, he was working on his short game. And you paid for it!”

Seventh, you won’t be elected with Republicans alone. The successful candidate must appeal to independents as well. In 2016, Mr. Trump promised his voters that they would get tired of winning. But he alienated independents to such a degree that they abandoned Republicans and joined Democrats, giving America Speaker Nancy Pelosi in 2018, President Biden in 2020, and Majority Leader Schumer in 2020. Just one Senate seat in 2020 would have brought the Democratic agenda to a complete halt. Most of Mr. Trump’s endorsements in highly contested races in 2022 lost in a midterms surprise that few people (including me) anticipated. If Mr. Trump is the nominee in 2024, are Republicans fully confident he will win independents this time? The ex-president surely loses if Republicans come to believe that a vote for Mr. Trump in the primaries means the election of Mr. Biden in the general.

And eighth, you need to penetrate the conservative echo chamber. You need at least one of these on your side: Mark Levin, Dennis Prager, Ben Shapiro, Newt Gingrich and, of course, Tucker, Hannity or Laura. Thanks to the Dominion lawsuit, we all know what Fox News hosts say in private. The challenge is to get them to be as honest in public. That requires a candidate as tough as Mr. Trump, but more committed publicly to traditional conservative ideology like ending wasteful Washington spending — and the ability to get it done. “Some people want to make a statement. I want to make a difference.”

Among the likely Republican rivals to Mr. Trump for the nomination, no one is coming close yet to doing some or all of this. Ron DeSantis has only mildly criticized Mr. Trump, preferring an all-out assault on Disney instead. No worries. He has plenty of time to get his messaging in order. But when he and his colleagues step onto the Republican debate stage in August, they will have but one opportunity to prove they deserve the job by proving they understand the Trump voter.

To be clear, if Mr. Trump runs exclusively on his administration’s record, he probably wins the nomination. So far, he has proved himself incapable of doing so. Most Republicans applaud his economic and foreign policy successes and his impact on the bureaucracy and judiciary, particularly in comparison to his predecessor and now his successor.

But that’s not the Donald Trump of 2023. The cheerleading stops for many when asked to evaluate Mr. Trump’s ongoing public comments and behavior. In 2016, the campaign was about what he could do for you. Today, it’s about what is being done to him. If he becomes increasingly unhinged, or if his opponents focus on his tweets, his outbursts and his destructive personality, a sizable number of Republicans could choose someone else, as long as they prioritize core, time-tested priorities like lower taxes, less regulation, and less Washington.

Republicans want just about everything Mr. Trump did, without everything Mr. Trump is or says.