Elon Musk’s rightward turn has led to a downward spiral for Tesla, and no amount of photo ops with Donald Trump will be able to save it, because the president is exactly what’s threatening the brand.

Donald Trump announced yet another round of tariffs against the European Union early Thursday, claiming that the “hostile” coalition of countries—who have been allies with the U.S. for decades—would ...

Michael Schneider, Alison Foreman, and Steve Greene contributed to this report.