WASHINGTON — Donald Trump's decision to strike Iran has been cheered by mainstream Republicans, but it has exposed deep fissures between the hawks and the isolationists in the "MAGA "movement that swept the self-styled peacemaker US president back to power.

Trump ran as an "America First "Republican who would avoid the foreign entanglements of his predecessors, tapping into his movement's unease about prolonged wars in Iraq and Afghanistan, as well as more recent conflagrations in Gaza and Ukraine.

Establishment Republicans — and in particular, the congressional party — rallied behind their leader after Saturday's military action, welcoming what many see as an about-face and rejecting claims that the president had violated the Constitution.

Beyond Washington's Beltway, some of the die-hard members of Trump's "Make America Great Again "coalition who follow him on the rally circuit also appear willing to give him the benefit of the doubt.

"I don't think we're going to end up in war," Jane Sisk, 63, a retired mother-of-six from Richmond, Virginia, told AFP. "I think Trump is leader, and he's going to just obliterate them, and there won't be any war."

However, the louder, more visible, more online faction of MAGA influencers and media personalities who oppose their government reaching beyond the United States' shoreline are desperate to sway Trump's supporters in the opposite direction.

In a lengthy post on X on Monday, far-right lawmaker Marjorie Taylor Greene lamented having traveled the country campaigning for Trump only to see him break his anti-interventionist promises to his supporters.

"Only 6 months in and we are back into foreign wars, regime change, and world war 3," she wrote.

"It feels like a complete bait and switch to please the neocons, warmongers, military industrial complex contracts, and neocon TV personalities that MAGA hates and who were never Trumpers!"

While the post was astonishing for its uncompromising language — Greene appropriated a Democratic talking point to add that Trump was "not a king" — it was far from the first sign of MAGA dissent.

'Tired from wars'

Thomas Massie, a House conservative who has piqued Trump's irritation with anti-war posts, told CBS that members of his faction within MAGA were "tired from all these wars".

And as Trump gave his televised address confirming details of strikes on Iranian nuclear sites, his former top strategist Steve Bannon told viewers of his online War Room show that the president has "some work to do" to explain his decision.

Hoover Institution fellow Lanhee Chen believes the president will hold his coalition together as long as they see Saturday's action as more akin to the 2020 US assassination of Iranian commander Qasem Soleimani than the start of a protracted war.

"I think you saw some of that disagreement leading up to last night. I haven't seen a lot of disagreement since then," Chen told NBC on Sunday.

In the latest J.L. Partners survey just ahead of the mission, 67 percent of "MAGA Republicans" agreed that "Israel's war is America's war" while only 20 percent wanted the country to remain on the sidelines.

"I don't think Trump's going to send soldiers over there," said Sisk, the Virginia supporter interviewed by AFP. "I don't think he's gonna get us involved in the war, just like he said."

Meanwhile, a Reuters/Ipsos poll that closed on Monday showed US people were similarly concerned about their country's military personnel stationed in the Middle East.

Some 79 percent of respondents said they worried "that Iran may target US civilians in response to the US airstrikes", and 84 percent said they worried in general about the growing conflict.

The poll, which surveyed 1,139 US adults nationwide, underscored deep divisions in the US over what Washington should do next and highlighted the political risks faced by Trump, whose presidential approval rating fell to 41 percent — the lowest level of his current term.

Only 32 percent said they supported continued US airstrikes, compared with 49 percent who said they were opposed. However, within Trump's Republican Party, 62 percent backed further strikes and 22 percent were opposed.

Agencies Via Xinhua