Elon Musk made a surprise appearance, accompanied by his son, in the middle of President-elect Donald Trump’s victory rally as rumors swirl of an already-fractured relationship between his Department of Government Efficiency (DOGE) counterpart,

The legions of lobbyists who have long worked the halls of Congress and federal agencies to secure their policy priorities have a new target: A shadow federal department run by the world’s richest man,

Mr. Musk has turned to Silicon Valley to help recruit executives who will take up unofficial positions across the federal government.