The Republican Not Heading to a July 4 Parade? Trump.

Both Mr. DeSantis and Mr. Scott will be at the July 4 parade in Merrimack, N.H., as will several other Republican presidential hopefuls: Mr. Burgum, former Representative Will Hurd of Texas, the entrepreneur and author Vivek Ramaswamy, and Perry Johnson, a Michigan businessman. Marianne Williamson, a long-shot challenger of President Biden for the Democratic nomination, will be there too as well as at an earlier parade in Wolfeboro — where Mr. DeSantis will also be.

Mr. Biden will be using a bit of presidential prerogative to host active-duty military families for barbecue at the White House. He will also have military and veteran families, caregivers and survivors on the White House lawn for Washington’s traditional fireworks — but not before some politicking at an event with the nation’s largest teachers union, the National Education Association.

Mr. Trump’s campaign evinces no concern that his absence from the stage will give his rivals any room to make up ground in the Republican primaries. After queries about his July 4 plans, his team released a memo Monday afternoon highlighting his campaign’s plans to celebrate the holiday in Iowa and New Hampshire — and calling out his dominant position in Republican primary polling.

Republican veterans don’t see much of an opening for Mr. Trump’s rivals either.

“He definitely plays by a different set of rules,” said David Kochel, a longtime Republican adviser and strategist in Iowa. Mr. Trump has made some recent adjustments with unscheduled stops at restaurants like Pat’s and, after his arraignment on the first federal felony charges ever levied on a former president, at Versailles, Miami’s beloved Cuban restaurant. He will be appearing with virtually the entire G.O.P. field at the Republican Party of Iowa’s biggest fund-raiser, the Lincoln Dinner, on July 28.

“But,” Mr. Kochel said, “his celebrity and the fact that he was president gives him more flexibility.”

The retail politics tradition in Iowa and New Hampshire may well be overrated, an artifact of a time before super PACs saturated airwaves, social media reached voters’ phones and celebrity pervaded the zeitgeist, regardless of who was in the diners and pizza joints.

“Retail has always been mostly theater, but now it’s all a performance for the cameras, not about meeting regular people and listening to their concerns,” said Fergus Cullen, a former chairman of the New Hampshire Republican State Committee.