Former Illinois congressman Joe Walsh wants Republicans to ditch President Trump next year. Two weeks ago, he wrote an op-ed headlined “Trump Needs a Primary Challenge,” and this week he tossed his hat in the ring as an actual GOP primary challenger. He joins former Massachusetts governor Bill Weld — one of the last remnants of the nearly extinct liberal wing of the GOP — the only other Republican to challenge Trump in 2020, and (perhaps) former South Carolina governor and congressman Mark Sanford, a fiscal hawk who is still mulling entry into the race.

Weld has run a muted and even genteel campaign, and thus has been nearly invisible both to the media and to Republican voters. Sanford seems halfhearted (at best) about taking on Trump. Walsh, by comparison, is a hard-edged heartland Republican with a history of taking red-meat conservative stances, with years of talk-radio experience, who could make a good run at matching Trump’s insulting rhetoric.

As a former Republican and a charter #NeverTrump conservative, I should be more excited about a Walsh, Weld or Sanford bid. It would be gratifying, at least in the short term, to see Trump respond to the few critics left in his own party. Instead, I’m concerned. And I think Walsh and his supporters are wrong about Trump needing a primary challenge.

The reality for Walsh or any other Republican contender is that Trump has a lock on the GOP electorate. In the latest Reuters/Ipsos poll, his approval among registered Republicans was 87 percent. A primary challenge won’t peel away those voters. Worse, if a primary bid morphs into a third-party candidacy, it might help Trump by splitting anti-Trump votes among multiple candidates.

If the Trump administration is the national emergency that many of us argue it is, and if the goal is getting Trump out of the White House, then that should be the only priority — and the most direct and reliable strategy is to encourage people, including Republicans, to vote for the Democratic nominee in 2020.

In a normal election year, it would make eminent sense to challenge Trump in the primaries. With a good economy at his back, it’s absurd that the president has a 54 percent disapproval rating in the RealClearPolitics polling average. That kind of number is an invitation to face a challenge, and as presidents from Jimmy Carter to George H.W. Bush learned the hard way, internal and third-party challenges can mean an Election Day loss.

But this is not a normal year and the GOP is no longer a normal political party. It’s a cult of personality. The people who like Trump’s record — his ignorant trade war, his loutish and sexist behavior, his siren-shrill racism, his staggering deficits, his hostility to America’s allies, and his affection for America’s enemies — are all going to vote for him again, anyway.

Republican voters won’t suddenly dump Trump if he’s attacked by Walsh, a tea party stalwart who won his House seat in the 2010 GOP wave, then lost two years later.

Walsh has already stumbled out of the gate, having to apologize for his offensive tweets and remarks over the years about everything from Islam to President Barack Obama’s race and place of birth.

And to what end? Republicans don’t want a less offensive version of Trump; they like the fully offensive version just fine. The people now wavering will come home to Trump when the Democratic nominee, whoever that is, is depicted as an America-hating socialist by the Republican Party and its media allies such as Fox News. And if they’re unlikely to choose Walsh, then they certainly don’t want anything to do with Weld, an old-school moderate with progressive views on social issues. Weld is offering a serious debate about fiscal discipline and a return to a rational foreign policy. But the party doesn’t want to have that debate. Republicans chose Trump in 2016, and there’s no evidence now of buyer’s remorse.

Some anti-Trump Republicans may see a primary challenge as protecting the GOP brand, in the vain hope that the party can recover from Trump, if and when the president is vanquished. They may be trying to think through various ways that Trump loses to the Democratic nominee while laying the groundwork for a 2024 GOP recovery.

It’s possible, for example, that an attack from Trump’s right forces him to spend money and attention on his flank rather than focusing on the Democrats early on, leaving him weakened enough entering the general election that the Democratic nominee prevails. It’s also possible that a primary would drive Trump into a deeper breakdown than the one he seems to be experiencing already, thereby scaring off enough of his wavering supporters who later will stay home or vote for a Democrat, again resulting in a Democratic victory.

These possibilities, though, are based on wishful thinking. The more plausible, and more dangerous, outcome of any Republican primary challenge is that it turns into a right-leaning, third-party effort in the general election that splits the anti-Trump vote, not Trump’s support, because it would allow right-leaning voters to slide into a second Trump term untainted by actually voting for the man himself. As in 2016, they could say that they voted neither for a Democrat — perish the thought — nor for Trump.

But Trump represents an existential crisis of American government. There is only one way to defeat him, and that is by amassing 270 electoral votes. Only a Democrat can do that, and so anything other than a vote for the Democratic nominee amounts to tacit — or, at best, unintentional — support for the incumbent.

To look at it this way isn’t to depict 2020 as a “Flight 93” election, that offensive characterization pushed by Trump’s enablers, in which voting Republican was cast as a last-ditch defense of the republic against an oncoming liberal horde. Rather, this is “a time for choosing,” as Ronald Reagan once put it to a very different Republican Party. Conservatives and right-leaning voters should have to decide what they stand for, not sit it out or duck behind a vote for Walsh or Weld.

For those who really want another Trump term but are unwilling to bear the moral stain of voting for him, there must be no safe harbor this time around. Other voters, however — those who truly believe Trump is unfit — should have to make the choice that removes him from office.