The U.S. has acting secretaries of defense and interior, attorney general, White House chief of staff, and heads of the Environmental Protection Agency, Office of Management and Budget, National Park Service, Bureau of Land Management, and other major federal agencies. For President Trump, this is a feature not a bug, he told CBS's Margaret Brennan in his pre-Super Bowl interview. "It's easier to make moves when they're acting," he said. "Really, I like acting because I can move so quickly. It gives me more flexibility."

To maintain that flexibility, the Trump administration is resorting to legally dubious means, putting policies at risk of falling to legal challenges. The large number of vacancies and temporary agency heads is also starting to earn Trump some pushback from Senate Republicans, The Washington Post reports. "It's a lot, it's way too many," said Sen. James Lankford (R-Okla.). "You want to have confirmed individuals there because they have a lot more authority to be able to make decisions and implement policy when you have a confirmed person in that spot."

In fact, according to a Congressional Research Service report published in July, "an action taken by any person" not complying with the Vacancies Act "in the performance of any function or duty of a vacant office ... shall have no force or effect." This hasn't been tested in court, yet, the Post notes, but legal experts say it's a plausible position. "Congress specifically sought to limit this sort of strategy," said Nina Mendelson, a law professor at the University of Michigan. "Legally binding actions taken by these officials would be subject to challenge."

Trump tends to blame Democrats for the numerous vacancies — 54 percent of his civilian executive branch nominations have been confirmed, according to the Partnership for Public Service — but Republicans have controlled the Senate for his entire presidency and Trump hasn't even nominated 150 of 705 Senate-confirmable posts. Peter Weber