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“Anyone slobbering for the US to become fully involved in the Israel/Iran war is not America First/Maga . . . We are sick and tired of foreign wars.”

These are the remarks of congresswoman Marjorie Taylor Greene, typically viewed as an unwavering supporter of Donald Trump. Her words underscore a significant rift within the Maga movement as the former US president considers employing American military force against Iran.

For numerous fervent Trump advocates, such a move would be seen as a profound betrayal. One of Trump’s enduring campaign messages was his denunciation of endless military conflicts. In a characteristic statement from 2019, he declared, “Entering the Middle East was the worst decision ever made.”

Numerous politicians and commentators most closely linked with the Maga movement have now overtly opposed increased US engagement in the conflict with Iran. Critics include Tucker Carlson, Steve Bannon, and former congressman Matt Gaetz. Carlson has penned in his newsletter, urging: “Abandon Israel. Let them manage their own conflicts,” while emphasizing, “Trump’s actions here will shape his presidential legacy.”

There are also signs that the anti-war right is linking up with the anti-war left. When Thomas Massie, a conservative Republican congressman, filed a House resolution seeking to block US involvement in the war this week, he swiftly got a host of co-sponsors from the Democratic left, including congresswoman Alexandria Ocasio-Cortez.

Trump himself has already jabbed back at his critics from within the Maga movement, calling Carlson “kooky” on social media. Meanwhile, supporters of America’s traditional role as world policeman (sometimes referred to as neoconservatives) within the Republican party have rallied to back Trump’s increasingly bellicose line on Iran. The supporters include senators Lindsey Graham and Mitch McConnell.

The split within Trump’s base extends to the rightwing media scene. Greene has condemned Fox News and the New York Post for cheerleading for the war. Carlson, meanwhile, has used his own media platform to go after the neoconservatives — conducting a notably aggressive interview with Ted Cruz, in which he accused the Texas Republican senator of cheerleading for a war against a country that he knew nothing about.

Vice-president JD Vance is known to have been sceptical about the case for war with Iran for many months. Buckley Carlson, Tucker’s son, is his deputy press secretary.

But Vance is now trying to act as peacemaker between the clashing factions within the Maga movement. In a post on X, he pleaded that Trump “has earned some trust on this issue”. He also tried to reassure uneasy Maga supporters that the president is “only interested in using the American military to accomplish the American people’s goals”.

An Economist/YouGov poll taken a few days ago suggested that 53 per cent of Trump supporters opposed the US joining the war, with just 19 per cent supporting involvement. That could change, if and when American planes start flying sorties over Iran. The early days of a war often create a “rally round the flag” effect.

But if the war goes wrong, there will be bitter recriminations. Iran could be the issue that breaks the Maga movement.

gideon.rachman@ft.com