The schedule seemed stacked against Donald J. Trump: four criminal trials in four cities, all in the same year he is running for president.

But rather than doom Mr. Trump, the chaotic calendar might just save him.

Mr. Trump, who as president helped reshape the federal judiciary, has already persuaded the Supreme Court to delay his trial in Washington. His lawyers have buried judges in Florida and Georgia in enough legal motions and procedural complaints that his cases there have no set trial dates, either.

The case in Manhattan, where Mr. Trump is accused of covering up a sex scandal during and after the 2016 presidential campaign, was the only one not mired in potential postponements.

Until now.

On Friday, Justice Juan M. Merchan, who is overseeing the case, delayed the trial at least three weeks, until mid-April.

It was hardly the first case to be delayed during Mr. Trump’s recent run of legal problems — and that is no accident. As the former president attempts to push each of his trials until after the election, he is relying on his most battle-tested strategy: Seek every delay available within the law.

The postponement of the Manhattan trial — the first prosecution of a former American president — stems from the recent disclosure of more than 100,000 pages of investigative records that may have some bearing on the case. Citing the records, Mr. Trump’s lawyers sought a 90-day delay of the trial, while the Manhattan district attorney, Alvin L. Bragg, proposed a delay of up to 30 days.