A New Trial Date. A New Primary Calendar.

This isn’t shaping up to be your usual presidential primary.

On Monday, the judge overseeing the election subversion case against Donald J. Trump in Washington set a March 4 trial date, putting his trial right in the heart of primary season.

If the trial goes as scheduled and lasts “no longer” than four to six weeks, as the government said in a filing, around two-thirds of the delegates to the Republican convention will be awarded during the trial of the party’s front-runner but, in all likelihood, before a verdict.

A March trial could easily become the center of gravity of the primary season — the fact that structures the opportunities available to Mr. Trump and his rivals. It could even start to affect the calculations of the candidates today.

As we’ve mentioned before, the possibility that Mr. Trump collapses under the weight of his legal challenges represents one of the likeliest ways he could lose the nomination. With Mr. Trump leading by more than twice as much as any front-runner who has ever gone on to lose a party nomination, it might even be the likeliest way he could lose.

Of course, there’s no guarantee that even imprisonment would be enough to defeat Mr. Trump in the primary. But if the sight of him in a courtroom is enough to weaken him, the trial date will be early enough for Mr. Trump’s rivals to capitalize.

Not all primaries are scheduled yet, but the March 4 start date is just one day before Super Tuesday, when Republicans are expected to vote in 13 states worth 35 percent of Republican delegates — including the mother lodes of California and Texas. Many Super Tuesday voters will have already cast ballots by mail or early in-person by the time the trial begins, but over the next six weeks, another 21 states and territories awarding 35 percent of all delegates will cast their ballots.

Overall, around 70 percent of delegates are expected to be awarded in the six weeks following March 4.

But a conviction, not a mere trial, has always loomed as the most obvious way that Mr. Trump’s support might collapse, even if there’s no guarantee that it would. When the special counsel proposed a Jan. 2 trial date a few weeks ago, it raised the possibility that Ron DeSantis might even be able to waltz to the nomination.

With a March 4 trial date, there probably won’t be any waltzing for Mr. DeSantis or anyone else. Just 19 percent of delegates will remain after April 15, and it’s possible it could be even longer before a possible conviction and sentencing, during which more delegates could be awarded.

If Mr. Trump survives politically during the trial, he could build an insurmountable delegate lead before hypothetical conviction and imprisonment — an event that could set off an unprecedented effort to remove Mr. Trump from the ballot or replace him as his party’s nominee at the Republican convention in July. Needless to say, ousting Mr. Trump at the convention would be exceedingly painful for Republicans.

For any candidates pursuing a “second-place strategy,” the proposed trial date creates some complications. The candidates will have an incentive to weaken Mr. Trump before and during the trial, while the former president is still presumably a viable or leading candidate. It might seem easy enough to capitalize on the trial of your political rival — but Mr. Trump has already survived multiple criminal indictments and come out stronger on the other side, as Republicans rallied to his defense. Perhaps Republicans will rally around Mr. Trump during a trial as well.

Waiting until a verdict to weaken him might be too late — or at least too late to avoid winning the usual way, by winning the most delegates.