Mr. Trump has been staging “Make America Great Again” rallies across the Rust Belt and in the critical swing state of Florida for months, and formally announced his re-election effort hours after he was sworn in in 2017. But as he and his campaign aides have watched Democratic presidential candidates declaring their candidacies and then announcing them a second time to attract a new round of attention from the news media, the Trump team has been eager for a distinctive event that would mark Mr. Trump’s official announcement.

But what exactly that would look like has for months been the source of internal debate among campaign aides and White House officials. Mr. Trump had initially planned an announcement in Florida, recommended by a number of advisers as the right launchpad for a politician who views pageantry as the key ingredient to a successful event. Those plans were briefly scrapped, however, in favor of a multistate tour.

Another plan called for a kickoff a few days earlier than June 18.

At one point, Jared Kushner, Mr. Trump’s son-in-law, who has been positioning himself as the unofficial campaign manager, pushed the idea of recreating Mr. Trump’s descending escalator ride at Trump Tower, but that idea was rejected because of the conflict of interest it might suggest between Mr. Trump’s business and his role as president.

Mr. Trump’s campaign ultimately returned to the original idea of a mammoth “Make America Great Again” rally in Florida, the bellwether on election night in 2016 that made it clear Mr. Trump was heading for a victory over Hillary Clinton, the Democratic nominee, and in 2020 a must-win state where his numbers so far are softer than the campaign would like.

The campaign was a taped-together operation in 2016, with a few desks strewn across an unfinished floor of Trump Tower. This time, it occupies a former trading floor in a sleek office tower in Arlington, Va., with sweeping views of the Potomac River.