One year ago, Donald J. Trump faced 91 felony counts across four criminal cases, enough for an ordinary defendant to brace for years behind bars.

But today, Mr. Trump still walks free — and is running for president. One of his cases was thrown out. The U.S. Supreme Court derailed another. A third is delayed indefinitely. And on Friday, in his only criminal case that actually made it to trial and scratched his legal Teflon, he pulled off one of his most surprising wins yet.

At Mr. Trump’s request, and without objection from prosecutors, the judge who presided over his criminal trial in Manhattan postponed his sentencing until after the election, in which Mr. Trump will square off against Vice President Kamala Harris for the presidency. The judge, Juan M. Merchan, had previously planned to impose the punishment on Sept. 18, during the heart of the campaign.

The decision from a judge who until now had propelled the case relentlessly forward is a surprising validation of the former president’s legal strategy to use his wealth and political status — and an assist from the Supreme Court — to drag out the case and diminish its impact on his campaign. The delay all but guarantees that, on Election Day, Mr. Trump will remain a felon, but also a free man.

Mr. Trump, who faces up to four years in prison for falsifying records to conceal a sex scandal, had sought the delay to buy time to challenge his conviction. The former president, who campaigns on claims that a corrupt court system has victimized him, also argued it would be unfair to face sentencing so close to Election Day, even though that timing was the result of his own stalling tactics.

But the delay will fuel a competing accusation of unfairness, as Mr. Trump’s critics perceive a justice system that treats normal defendants one way, and the singular Mr. Trump another. While sentencing delays are routine, New York law instructs judges to impose a punishment “without unreasonable delay,” and they often do so within six weeks of conviction. Mr. Trump has now bought himself six months.