On Friday, Mr. Trump traveled to Atlanta for an overtly political event: he delivered remarks at the Black Voices for Trump Coalition Rollout, and the campaign paid for his travel. But there have been many other events that were not designated as campaign events, but may as well have been. And for many voters, that’s part of his appeal.

“He knows there’s a core that adore him, but also a sizable number of people that want to see Washington disrupted,” said Jonathan Turley, a law professor at George Washington University . “This merging of the political with the official works with that narrative.”

In the past, presidents went out of their way to ensure their official remarks did not veer into political territory. Copies of speeches were meticulously edited by the White House Counsel’s Office, which would flag lines that could violate the Hatch Act, a Depression-era law that prohibits federal employees from engaging in political activities while on the job.

The president is not subject to the Hatch Act but everyone who works for him is. Speechwriters and policy advisers who helped prepare those remarks, for instance, could be in violation of the act if they were crafting an overtly political speech for the president. But the Hatch Act is ultimately self-enforcing, and toothless if the president chooses to ignore warnings from White House lawyers about possible violations.

President Barack Obama’s aides said they took the law seriously.

“The reason we were so cautious about it was the fear the campaign would then have to pick up the tab for the event,” said Dan Pfeiffer, a former communications director for Mr. Obama. “The Air Force One travel, the cost of the venue — that’s a huge bill to pick up for a stray sentence.”