The Trump era is scrambling traditional partisan loyalties, sometimes to disorienting effect for leading thinkers on the right. The Never Trump faction of the Republican Party has been a political failure, in that it was unable to stop Donald Trump’s election, but remains a lively intellectual force. Some of the harshest criticism of the Republican president has come from mainstream conservative columnists like Max Boot, Jennifer Rubin, and George Will, and in respected conservative journals like National Review, Commentary, and The Weekly Standard. Bill Kristol, the scion of neoconservatism and a majordomo of the GOP establishment, tweeted last week:

To some centrists and liberals, Kristol’s ideological crisis presents a political opportunity. If many erstwhile conservatives are opposed to Trump, why not form a broad anti-Trump coalition that crosses old party lines? Benjamin Wittes, a fellow at the Brookings Institute with impeccable centrist credentials, on Sunday tweeted a manifesto calling for exactly that:

“We have grave disagreements about social issues, about important foreign policy questions, about tax policy, about whether entitlements should be reformed or expanded, about what sort of judges should serve on our courts,” Wittes wrote. “#IBelieve in putting them all aside. #IBelieve in a temporary truce on all such questions, an agreement to maintain the status quo on major areas of policy dispute while Americans of good faith collectively band together to face a national emergency. #IBelieve that facing that national emergency requires unity.”

At least a few liberals are on board. “Ben, where do I sign?” wrote The Daily Beast’s estimable liberal columnist, Michael Tomasky. He argued on Tuesday that an anti-Trump Popular Front “could be a powerful and influential thing if Wittes can get 20 or 30 or 50 prominent people on both sides to sign a statement of principles, and thousands or maybe tens of thousands of regular citizens to co-sign on Facebook.”

The basic principles of this coalition, as outlined by Tomasky, are hard to argue with: “Commitments to the First Amendment; to transparent government; to getting to the bottom of Russia; to science and evidence; to no Muslim-bashing, ‘full stop’; to fighting presidential abuse of power.” Such noble goals could only be opposed by the hopelessly sectarian, he suggests:

The natural response of some partisans on both sides would be to refuse to commit to a project like this because of the past positions of some who might join it. “I’ll never work with Bill Kristol!”, that kind of thing. Well, Bill Kristol’s done a lot of things I don’t like. And I’ve probably done a lot of things he didn’t like, though I have only a fraction of his influence, so I’ve never helped kill a major piece of legislation (Hillary’s health care bill) or push the country toward war. But I’m ready even to forget Iraq. That’s the very essence of Popular Frontism. If Kristol wants to stop Trump and is willing to commit to Wittes’ principles, then we should be too.

Wittes and Tomasky are half right. Opposing Trump’s authoritarianism and corruption shouldn’t be a partisan issue. The distaste that conservative pundits like Kristol and Rubin have for Trump does present a chance for Democrats to reach at least some voters and lawmakers on the right, helping to fray the Trump coalition. And articulating a politics in defense of democratic norms is a necessary response not just to Trump himself, but to extremism broadly.

But an anti-Trump Popular Front could only work in an ad hoc fashion on specific issues, like those outlined by Tomasky and Wittes. It can’t supersede partisan politics even on a temporary basis because success for the two major parties depends on energizing their respective bases, and nationwide elections are never more than two years away. To run on a depoliticized program of centrist anti-Trumpism would demoralize and demobilize Democratic voters, a lethal move for the left since Trump has been successful at mobilizing hardcore Republicans.

We also don’t need to speculate on whether an anti-Trump Popular Front would work. It was attempted in last year’s election. Hillary Clinton went out of her way to distinguish between Trumpism and old-fashioned Republicanism, as represented by the likes of Paul Ryan and Mitt Romney, and her ads cited Republican critics of Trump. The Democratic National Convention even gave pride of place to centrist heroes like Michael Bloomberg. The result of this outreach: Clinton outperformed expectations in traditionally Republican leaning suburbs, but underperformed among Democratic voters, a sufficient number of whom ended up voting for Trump, staying home, or voting for a third-party candidate, thus costing Clinton the election.

Since winning the presidency, Trump has pursued a hard-right Republican agenda, with mixed success: nominating conservative judges, cutting taxes for the rich, deregulating the financial and fossil fuel industries, repealing Obamacare, and disengaging from international agreements. Democrats have successfully mobilized their own base in opposition to this agenda, and the recent elections in Virginia suggest that this could be a winning formula for the party in the 2018 midterms. If Democrats sign on to Wittes’s “temporary truce,” focusing entirely on good government issues, they would be ignoring the core concerns of their voters.

The two major parties are deeply divided along political lines because there is genuine political division in America. Trump has shown that this extreme partisanship is so strong, it will persist even when one party is led by a deeply unpopular and unfit standard bearer. Most Republicans are sticking with Trump because even if they dislike him, they hate Democrats more. And even the Republicans who most hate Trump remain staunchly opposed to Democrats who are most popular with the left. On Tuesday morning, Kristol tweeted:

In agreeing to an anti-Trump Popular Front, Democrats would end up with allies like Kristol who will probably sit out the 2020 election anyway—or vote for a symbolic candidate—since they’ll hate both major-party candidates. That would lead Democrats to yet another political defeat. Trump is indeed a national emergency, but there is no escaping the logic of partisan politics. The best way to take down the president is to strengthen the Democratic Party from within, not dilute it with fickle fellow travelers.