The president’s vague threats make booting out his political enemies sound easy. Here’s what he can actually do.

President Trump announced Wednesday that Transportation Secretary Sean Duffy will temporarily lead the National Aeronautics and Space Administration, weeks after Mr. Trump withdrew an Elon Musk-linked entrepreneur as his pick to lead the space agency.

As the Tesla boss has ramped up threats to form a new third party after Republicans passed Trump’s mega-spending bill, Musk also purged his X account of House Speaker Mike Johnson, the White House’s Rapid Response account, Republican Congresswoman Nancy Mace, Energy Secretary Chris White, and MAGA activist Scott Presler.