President Trump’s political base is splintering over the prospect that the U.S. could join Israel’s assault on Iran—and the White House is trying to quell the backlash.

The prospect of a U.S. strike against Iran has exposed divisions in the coalition of supporters that brought President Donald Trump to power, with some of his base urging him not to get the country involved in a new Middle East war.

Donald Trump’s hints that he may dispatch the US military to help Israel destroy Iran’s nuclear program has spurred a revolt from his typically faithful America First base, further dividing a party already struggling to unite around the president’s second-term agenda.