The brief détente between Elon Musk and President Donald Trump took its last breath over the weekend, as the billionaire and once top Republican donor announced he would form a new political party.

Tech billionaire Elon Musk’s third-party effort “makes as much sense as selling sand in the desert,” according to CNN’s chief data analyst Harry Enten.

If Musk is able to pry away Republican votes in a few hotly contested districts, he could undermine GOP control of Congress and make it harder for President Donald Trump to pull off his agenda. Musk’s new party could even spend its way into a few congressional seats.