Trump ran on a platform of peace. His war may have cost Republicans the midterms | Mohamad Bazzi

For much of his political career, Donald Trump ranted at past US presidents who got the US entangled in endless foreign conflicts. He used it as a cudgel to belittle his predecessors, calling George W Bush’s decision to invade Iraq in 2003 “the worst single mistake ever made in the history of our country”. Trump also regularly derided the occupation of Afghanistan as “a total disaster”.

Then Trump decided to launch his own disastrous war against Iran eight months ago. And that conflict may well have cost Republicans control of Congress in last week’s midterm elections.

In exit polling conducted by NBC News, three-quarters (74%) of voters said the war was a “crucial” or “major” factor in their vote for Congress. And 63% said the Trump administration made “the wrong decision” by taking military action against Iran.

The midterms turned out to be a massive public repudiation of the Iran conflict – and of the US legacy of forever wars that followed the terrorist attacks of 11 September 2001.

It was no secret that most Americans had soured on foreign interventions and were opposed to Trump starting new ones. In January, a poll by Quinnipiac University found that 70% of voters opposed an attack on Iran – a total reversal from US public opinion ahead of the Iraq invasion more than two decades ago, when polls showed 72% of Americans supported that war in its early days.

But Trump was blinded by hubris, thinking he could achieve a quick military victory and overthrow the regime that took power after Iran’s Islamic revolution in 1979.

The Iranian regime fought hard for its survival, retaliating against the joint US-Israeli attack by destroying oil pipelines and other energy infrastructure in neighboring Gulf countries, and largely closing the strait of Hormuz. Before the conflict, more than a fifth of the world’s oil and natural gas supplies passed through the crucial waterway each day.

The war led to a global increase in energy prices and other costs – and American voters took out their widespread anger at the economic fallout against Trump and his Republican party.

It also didn’t help Trump that he ran for and won the presidency in 2024 as an anti-war candidate. He promised to negotiate an end to Russia’s invasion of Ukraine and Israel’s war against Gaza, among other conflicts that he argued had been prolonged by his Democratic opponents, Joe Biden and Kamala Harris.

“If Kamala wins, only death and destruction await because she is the candidate of endless wars. I am the candidate of peace,” Trump said at a November 2024 rally in Michigan, a swing state he won partly with support from Arab and Muslim American voters. Those voters, many of whom have relatives in the Middle East, were angry at the Biden administration’s unwavering support for Israel as it expanded its war from Gaza into Lebanon and other countries in the region.

Beyond his free-wheeling campaign rallies, Trump used his most important speeches to portray himself as an “America First” president who opposes foreign military adventurism. It became a cornerstone of his Maga (Make America Great Again) movement. “I’m not going to start a war. I’m going to stop wars,” Trump declared in his 2024 election night victory speech in Florida.

In the end, US voters remembered Trump’s many promises to avoid the same kind of regime-change wars started by his predecessors – and they punished Republicans for Trump breaking those pledges.

As the extent of Republican losses in House, Senate and gubernatorial races nationwide became clear last week, JD Vance posted a lengthy statement on Twitter/X blaming the Republican wipeout on the Iran conflict. “The reason we lost is the war,” Vance wrote, explaining that voters who had supported Trump in 2024 showed up in the midterms to vote for Democrats because they were angry about the war, higher prices and other economic fallout.

Vance also suggested that the Trump administration had abandoned its “America First” agenda – an attempt by the vice-president to lay his claim as the legitimate heir to the Maga coalition after Trump, who can’t run for re-election in the 2028 presidential race.

But the movement may have fractured irreparably, thanks to the Iran war and the devastating Republican losses in the midterms.

Let’s not forget that Vance was once a fierce critic of the president, who then cozied up to Trump when it became clear he would be the leading Republican candidate in 2024.

In fact, Vance helped promote the narrative to a weary American public that Trump would avoid getting embroiled in new conflicts, unlike his Democratic opponents. In 2023, Vance endorsed Trump by writing a Wall Street Journal opinion article headlined: “Trump’s Best Foreign Policy? Not Starting Any Wars.”

“My entire adult lifetime has been shaped by presidents who threw America into unwise wars and failed to win them,” Vance wrote, outlining failed US interventions in Afghanistan, Iraq, Libya and elsewhere. At the time, Vance was auditioning for the role as Trump’s running mate – and his record as a US Marine who served in Iraq, and later turned against the war, made him appealing to Trump’s Maga base.

Yet Vance did not dare to publicly break with Trump at the start of the Iran war in late February, when the move would have represented a greater political risk but Vance could have made a bigger difference in the conflict’s trajectory.

Today, even Trump is acknowledging that the war played a major role in the Republicans’ midterm losses. When he was asked on 4 November about Vance’s assessment of the election, Trump said: “I think it’s largely true because it drove the gasoline [prices] up a little bit short-term.”

But because Trump refuses to publicly admit making any mistake, he continues to defend his catastrophic decision to attack Iran. “If I had to do it again, I’d have to do it again,” Trump added, while touring his half-finished White House ballroom the day after the midterms. “You can’t let Iran have a nuclear weapon.”

Of course, Trump never bothered to make a robust case to Americans, or even to Congress, explaining how Iran posed a threat to US interests that would justify launching a new war in the Middle East. Unlike the Bush administration in the lead-up to its invasion of Iraq, Trump didn’t even try to build his case based on lies and manipulated intelligence.

And so American voters swiftly punished Trump and his Republican enablers for dragging the US into yet another open-ended war.

• Mohamad Bazzi is a Guardian US columnist. He is also director of the Center for Near Eastern Studies, and a journalism professor, at New York University