Rep. Liz Cheney (R-Wyo.) all but announced her 2024 presidential run on Tuesday. But the big question looming over her potential candidacy is how she expects to take down defeated former president Donald Trump in a party still in his thrall.

As we leave here, let us resolve that we will stand together — Republicans, Democrats and independents — against those who would destroy our republic. They are angry and they are determined, but they have not seen anything like the power of Americans united in defense of our Constitution and committed to the cause of freedom. There is no greater power on this earth, and with God’s help, we will prevail.

In the context of a presidential primary, it will take not only decent Republicans but millions of Democrats — and even President Biden — to help her eliminate Trump in the primary, force the nomination to go to the convention or do enough damage to set him up for defeat in the general election.

It starts with Biden declaring his reelection bid (which he seemed intent on doing anyway), thereby effectively eliminating a Democratic presidential primary. That then frees up Democrats to vote in the GOP primaries (as some, but not enough, did in deep-red Wyoming on Tuesday to support Cheney). In some cases, they will be able to vote in open primaries. In other states, they will need to re-register to vote in Republican primaries.

There is nothing nefarious about this. To the contrary, this would turn the Republican primary into a bipartisan affair and referendum on democracy. In essence, Cheney will be starting the general election against Trump right away.

This will no doubt raise several questions:

First, didn’t she try this in Wyoming? Not really. With more than 70 percent of voters registered as Republicans — and a Democratic primary in operation — the math simply did not work. But consider a state where the registration is heavily Democratic, such as New Jersey or New York. It would take only a fraction of those Democrats voting in the GOP primary to bring down Trump’s share of the vote. And remember, this is not so much about Cheney actually winning (a remote possibility) but about creating a national anti-Trump movement. As Eugene McCarthy did against President Lyndon B. Johnson in 1968, Cheney might undermine Trump’s coronation just by taking a significant share of the primary vote in early contests.

Second, would Democrats have to do this in every state? No. It wouldn’t make much sense for Democrats to replay the Wyoming primary, or to lend their effort in similarly deep-red states. However, if a significant number of Democrats were, for example, to help her out just in states with a robust Democratic registration, that might be enough to deny Trump a majority of the GOP delegates. It certainly would help educate the electorate as a whole, which is ultimately Cheney’s audience.

Finally, how does she run ostensibly for the Republican nomination without putting off her Democratic allies? She would likely run the same sort of one-issue campaign she did in Wyoming. It will need to be an explicit referendum on democracy, the rule of law and the risk of a second Trump term. That’s what she has in common with Democrats — and what her political career is now all about.

Again, Cheney likely wouldn’t run to win herself but to stop Trump from winning — in the primary if possible and, if not, in the general election. This wouldn’t be a traditional campaign. Her aim wouldn’t be self-promotion but Trump’s defeat. Her message wouldn’t be about policy but preserving democracy and weakening Trump’s grip on the party. As she said, there can be no serious policy debates unless we secure democracy first. And the GOP can never become a decent pro-democracy party so long as Trump remains its leader.

To accomplish this, Cheney will need to turn a partisan primary into a national crusade enlisting Republicans, Democrats and independents against Trump. It will take a unique primary strategy unlike anything we’ve seen to remove a unique threat to our democracy.

Opinion by Jennifer RubinJennifer Rubin writes reported opinion for The Washington Post. She is the author of “Resistance: How Women Saved Democracy from Donald Trump.”