Tesla shares tumbled after CEO Elon Musk announced that he plans to start a new political party, reigniting concerns that his attention will turn away from running the EV maker and that a public feud with President Trump will escalate.

It’s a brilliant public relations move. Musk’s goading of the president is basically impossible to ignore and is guaranteed to produce a response. If Musk pursues his America Party, you can expect headlines for the next 18 months, with Trump and other Republicans attacking him personally.