Waltz’s fate was sealed by his inclusion of a journalist on a sensitive Signal group chat in March. But he had been clashing with other top officials since early in the administration, including over whether to pursue military action against Iran, senior officials and Trump advisers said Friday.

It wasn’t just Signalgate that led to Mike Waltz being canned as President Donald Trump‘s national security adviser. Before that scandal, Waltz had already angered Trump by going behind his back to talk with Israeli Prime Minister Benjamin Netanyahu about waging war on Iran,

While Secretary of State Marco Rubio will fill in temporarily as national security adviser, President Trump is likely to follow his own often quixotic instincts.