Talk show host Tucker Carlson broke with President Donald Trump on Iran on Friday, writing in a scathing commentary in his daily newsletter that the United States should “drop Israel” and “let them fight their own wars.”

“If Israel wants to wage this war, it has every right to do so. It is a sovereign country, and it can do as it pleases,” Carlson wrote of Israel’s preemptive strike on Iran’s nuclear facilities. “But not with America’s backing.”

Trump, for his part, has endorsed Israel’s attacks, which he called “very successful,” and underscored in an interview with Fox News on Thursday night that the U.S. would defend Israel if Iran retaliates. He also warned that the situation “will only get worse” if Iran does not agree to a nuclear deal “before there is nothing left.”

In recent days, Carlson has argued that fears of Iran obtaining a nuclear weapon in the near future are unfounded and said that a war with the Islamic Republic would not only result in “thousands” of American casualties in the Middle East but “amount to a profound betrayal of” Trump’s base and effectively “end his presidency.”

Carlson reiterated that claim in his newsletter, accusing Trump of “being complicit in the act of war” through “years of funding and sending weapons to Israel.”

Direct U.S. involvement in a war with Iran, he said, “would be a middle finger in the faces of the millions of voters who cast their ballots in hopes of creating a government that would finally put the United States first.”

“What happens next will define Donald Trump’s presidency,” he concluded.