After the relationship between President Trump and Elon Musk exploded into warfare Thursday, Mr. Trump suggested that he might eliminate the tech titan’s federal contracts.

“The easiest way to save money in our Budget, Billions and Billions of Dollars, is to terminate Elon’s Governmental Subsidies and Contracts. I was always surprised that Biden didn’t do it,” Mr. Trump posted on his social media platform.

That’s not as easy as Mr. Trump’s implies. The Pentagon and NASA remain intensely reliant on SpaceX, Mr. Musk’s rocket launch and space-based communications company, to get to orbit and move government data across the world.

But there are options available to the president that could make Mr. Musk’s relationship with the federal government much more difficult than it has been so far in Mr. Trump’s second administration.

Mr. Trump’s most accessible weapon to punish Mr. Musk is the ability to instruct federal regulators to intensify oversight of his business operations, reversing a slowdown in regulatory actions that benefited Mr. Musk’s businesses after Mr. Trump was elected.

“In an administration that has defined itself by reducing regulation and oversight, it would not be difficult to selectively ramp up oversight again,” said Steven L. Schooner, a former White House contracts lawyer who is now a professor at George Washington University.