WASHINGTON — Temporary status is a seemingly permanent condition of the Trump administration.

The resignation of Kirstjen Nielsen as homeland security secretary on Sunday means that another cabinet officer who reports directly to President Trump will have the word “acting” next to the official title at a major department of government.

Interim secretaries are also in place at the Departments of Defense and of the Interior, and at the Office of Management and Budget, the Small Business Administration and ambassador’s office at the United Nations. Mick Mulvaney, Mr. Trump’s chief of staff, is also serving in an acting capacity.

“I like acting. It gives me more flexibility. Do you understand that?” Mr. Trump told reporters in January before departing to Camp David. “I like acting. So we have a few that are acting. We have a great, great cabinet.”

But there are concerns about having men and women in such high-level jobs without having been subjected to Senate confirmation for those posts. Leaving cabinet secretaries unconfirmed in their roles could give the president even more leverage over them, or could leave them without full authority in the job.