Don’t kid yourself: President Donald Trump could absolutely win re-election. The old man is preternaturally intuitive, resilient when most would wilt, and just plain lucky. Plus, just as Ferris Bueller drove Ed Rooney insane, Trump has a knack for goading his political opponents to self-destruct. But, as I like to caution Republicans, you never know what might happen in 2020 if the Democratic Party nominates a presidential candidate who is likable, trustworthy, and . . . not under investigation by the Federal Bureau of Investigation.

Perhaps that is why, as Republicans sift through the wreckage of another Trump meltdown, the demolition of their House majority in the midterm elections two months prior, the ouster of James Mattis, and a holiday shutdown over the border wall, party operatives were spending the most wonderful time of the year trying to figure out what it’s going to take to avoid an even worse fate. For as much as some Republicans would like to see the president return to Trump Tower, they’re not willing to give up the presidency. And so, as the 2020 primary season begins, they are beginning to make a list of Democratic candidates that they think Trump can credibly beat.

Without naming names, I asked several senior Republican insiders which Democrat, or Democrats, at the top of the opposition ticket would most reassure them about 2020. Without exception, Elizabeth Warren, the 69-year-old progressive senator from Massachusetts, topped every wish list. “There’s a lot of Hillary Clinton in her,” said a veteran Republican operative in D.C. who hails from the Midwest and keeps a close eye on the heartland. “She’s elitist and doesn’t appear very nimble. It would be hard for her to expand her base or reach directly into Trump’s base.” Close behind were Senators Cory Booker of New Jersey and Bernie Sanders of Vermont, who, technically, is not a member of the Democratic Party.

There’s a theme here. For all of Trump’s faults—and Republicans who make a living trying to win elections tend to be honest about most of them, albeit privately—the United States is still a center-right country, at least according to the data the G.O.P. trusts. And Trump brings a certain gravitas to the job, despite his periodic tendency to diminish the presidency. A lightweight Democratic contender too enthralled with, or captive to, leftist dogma is an opponent that even a politically pockmarked Trump can exploit.

To wit, Trump’s domestic populism, fraught with cultural nativism such as it is, looks far more reasonable when stacked against dubious promises of free stuff (actually financed by the taxpayers, so, not free.) Trump’s “America First” nationalism, fraught with a troubling pullback from the post–World War II, bipartisan foreign policy consensus and disregard for America’s unique role as global protector of the liberal world order such as it is, looks less drastic when stacked against . . . a Democrat who essentially wants to do the same thing, minus the military buildup—and the tweets.

But more than all of that, Republicans are happy to run against any progressive who tries to compete with Trump on Trump’s terms. Exchanging barbs on social media platforms; name-calling; questioning his capacity mentally, physically, and the like. As much as the Democratic base might be clamoring for a standard bearer to force-feed the president a dose of his own medicine, there is no beating the genuine article at the game he perfected. Trump is too quick and too shameless, and that approach offers little change to voters who want to turn the page from the chaos and anxiety that has characterized the current era. “A Democrat is not going to defeat Trump by being more brash, blustering, and strident. They will win over voters they need to retake the ‘blue wall’ states by connecting with those voters on substance but presenting an alternative to his leadership style,” a Republican consultant told me in an e-mail.