This suggests that a reaction from consumers who dislike Mr Musk’s antics are only one reason for falling sales. An updated Model Y, Tesla’s best-selling vehicle, has just gone on sale. In preparation Tesla ran down inventory of the old model, crimping supply. Customers doubtless held off purchases until the new car was available.

Elon Musk was considered just another eccentric genius, but recent developments have put him at the center of American politics.