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.

Squinting in the sun with Elon Musk, Trump stood next to five Tesla vehicles, holding a piece of paper with handwritten notes about their features and costs. Trump said he would purchase a car himself at full price.