The Republican front-runner is facing a growing tangle of criminal and civil trials that will overlap with next year’s presidential primaries.As former President Donald J. Trump campaigns for the White House while multiple criminal prosecutions against him play out, at least one thing is clear: Under the laws of physics, he cannot be in two places at once.Generally, criminal defendants must be present in the courtroom during their trials. Not only will that force Mr. Trump to step away from the campaign trail, possibly for weeks at a time, but the judges overseeing his trials must also jostle for position in sequencing dates. The collision course is raising extraordinary — and unprecedented — questions about the logistical, legal and political challenges of various trials unfolding against the backdrop of a presidential campaign.“The courts will have to decide how to balance the public interest in having expeditious trials against Trump’s interest and the public interest in his being able to campaign so that the democratic process works,” said Bruce Green, a Fordham University professor and former prosecutor. “That’s a type of complexity that courts have never had to deal with before.”More broadly, the complications make plain another reality: Mr. Trump’s troubles are entangling the campaign with the courts to a degree the nation has never experienced before and raising tensions around the ideal of keeping the justice system separate from politics.Mr. Trump and his allies have signaled that they intend to try to turn his overlapping legal woes into a referendum on the criminal justice system, by seeking to cast it as a politically weaponized tool of Democrats.Already, Mr. Trump is facing a state trial on civil fraud accusations in New York in October. Another trial on whether he defamed the writer E. Jean Carroll is set to open on Jan. 15 — the same day as the Iowa caucuses. On Jan. 29, a trial begins in yet another lawsuit, this one accusing Mr. Trump, his company and three of his children of using the family name to entice vulnerable people to invest in sham business opportunities.Because those cases are civil, Mr. Trump could choose not to attend the trials, just as he shunned an earlier lawsuit by Ms. Carroll, in which a jury found him liable for sexual abuse.But he will not have that option in a criminal case on charges in New York that he falsified business records as part of covering up a sex scandal shortly before the 2016 election. The opening date for that trial, which will most likely last several weeks, is in late March, about three weeks after Super Tuesday, when over a dozen states vote on March 5.Jack Smith, the special counsel leading two federal investigations into Mr. Trump, has asked the judge overseeing the indictment in the criminal inquiry into Mr. Trump’s hoarding of sensitive documents to set a trial date for late 2023.But on Tuesday — the same day Mr. Trump disclosed that federal prosecutors may charge him in the investigation into the events that culminated in the Capitol riot — his defense lawyers argued to Judge Aileen M. Cannon that she ought to put off any trial in the documents case until after the 2024 election. The intense publicity of the campaign calendar, they said, would impair his rights.Mr. Trump has long pursued a strategy of delay in legal matters, seeking to run out the clock. If he can push his federal trial — or trials, if he is ultimately indicted in the Jan. 6 inquiry — beyond the 2024 election, it is possible that he or another Republican would win the presidency and order the Justice Department to drop the cases.A president lacks the authority to quash state cases, but even if Mr. Trump were to be convicted, any inevitable appeals would most likely still be pending by Inauguration Day in 2025. If he is back in office by then, the Justice Department could also raise constitutional challenges to try to defer any additional legal proceedings, like a prison sentence, while he is the sitting president.In making the case for delaying the trial until after the election, Mr. Trump’s defense lawyers contended on Tuesday that Mr. Trump was effectively squaring off in court against his 2024 rival, President Biden.“We don’t know what’s going to happen in the primaries, of course, but right now, he’s the leading candidate,” said Todd Blanche, one of Mr. Trump’s lawyers. “And if all things go as we expect, the person he is running against — his administration is prosecuting him.”But David Harbach, a prosector on Mr. Smith’s team, said Mr. Trump was “no different from any other busy important person who has been indicted.” He called the claim of political influence “flat-out false,” seemingly more intended for “the court of public opinion” than a court of law.“The attorney general appointed the special counsel to remove this investigation from political influence, and there has been none — none,” he said.Judge Cannon, who has not yet made a decision about the eventual trial date, indicated that in considering delay, she believed the focus should be not on the campaign but on legal issues, like the volume and complexity of classified evidence.Setting a trial date for the documents case is the first and most basic logistical issue. But the possibility of indictments from two inquiries into Mr. Trump’s attempts to stay in power after the 2020 election, the federal investigation led by Mr. Smith and a state investigation overseen by Fani T. Willis, a district attorney in Georgia who has signaled that charges could come in August, may soon bump up against that.There is no overriding authority that acts as an air traffic controller when multiple judges are deciding dates that could conflict. Nor are there rules that give federal or state cases precedence or that say that any case that was charged first should go to trial first.Brandon L. Van Grack, a former prosecutor who worked on the Russia investigation led by the special counsel Robert S. Mueller III, pointed to that inquiry as an example. Prosecutors brought charges against Mr. Trump’s former campaign chairman, Paul Manafort, in two jurisdictions, first in the District of Columbia and then in the Eastern District of Virginia, but the trials took place in reverse order.“There was sensitivity to hearing dates, and it was incumbent on counsel to educate both judges on the scheduling and conflicts, but there wasn’t a rule that said the District of Columbia matter was charged first and therefore went to trial first,” he said. “It’s judicial discretion.”As an informal practice, Mr. Green said that judges overseeing potentially conflicting matters sometimes call each other and work out a calendar. No procedural rule authorizes such conversations, he said, but it is considered appropriate.Looming over Mr. Trump’s legal peril is an unwritten Justice Department norm known as the 60-day rule. As a primary or general election nears, prosecutors should not take overt actions that could improperly influence voting.It is not clear, however, how that principle applies to matters that are already public and so less likely to alter a candidate’s image. Notably, Raymond Hulser, a veteran prosecutor who has been consulted for years about how to apply the 60-day rule, is a member of Mr. Smith’s team.Further complicating matters, Mr. Trump has hired some of the same defense lawyers to handle multiple investigations against him, leaving them stretched for time.Christopher Kise, another lawyer for Mr. Trump, cited the former president’s crowded legal calendar at the hearing on Tuesday. Not only did Mr. Kise indicate that he would need to prepare for the fraud-related trials in October and January, but he also pointed to Mr. Blanche’s role in the criminal trial in March involving falsified business records in New York.“So these are the same lawyers dealing with the same client trying to prepare for the same sort of exercises, and so I think that’s highly relevant,” Mr. Kise said.Several legal experts said that while people have a Sixth Amendment right to choose their legal representation, it is not absolute. They noted that judges could tell defendants that, if their chosen lawyers are too busy to take on additional matters in a timely manner, they must hire others.Such an order would give Mr. Trump something more to complain about to an appeals court, said Professor Green, who added, “I think it’s probably a losing argument.”Alan Feuer More