Vice President JD Vance has blamed the war on Iran for the Republican Party’s sweeping defeat in Tuesday’s midterm elections, in which Democrats won control of both chambers of the United States Congress.

“The reason we lost is the war. The president himself said so last night,” Vance wrote in a lengthy post on X on Wednesday.

Senator Ted Cruz, a longtime Iran hawk, also turned on the conflict, saying in an episode of his podcast on Wednesday that it “should have been brief, decisive, and over”.

This week, President Donald Trump has insisted that he has no regrets. “I did the right thing. I would have done it again,” he told The Wall Street Journal about launching a war on Iran alongside Israel in February.

So, why are Trump’s allies breaking ranks, and what does it mean for the war? Here’s what you need to know: Vance, a likely 2028 presidential candidate and heir apparent to Trump’s Make America Great Again (MAGA) movement, questioned whether the war had been worth the political cost.

“If you’d like to argue it was worth it, that losing the Senate for the next 6 years was worth it, then do so,” he wrote.

Citing an unnamed pollster, Vance said ending the Iran war and “changing our relationship with Israel” were two of the top four answers given ahead of this week’s midterms by Americans who voted for Trump in 2024 but planned to vote for Democrats this year.

Cruz’s criticism came from another direction. The war had “dragged on too long”, he said in a post on X, adding that Washington “should never, under any circumstances, give the Ayatollah billions of dollars”.

He was apparently referring to the June memorandum of understanding signed by Washington and Tehran, which included a $300bn fund to help rebuild post-war Iran among several topics for discussion in wider peace talks. The proposal for the fund triggered hefty pushback from conservative lawmakers, including Cruz, who said it amounted to a massive payout for the Iranian regime. The June agreement, which provided for a ceasefire at the time, quickly fell apart, however.

Trump told reporters at the White House on Wednesday that Vance’s assessment was “largely true”, blaming higher fuel prices, as a result of the war, for Americans turning against his party. But the president insisted the war was necessary to stop Iran from obtaining a nuclear weapon.

Republicans are positioning themselves for the 2028 presidential election, which Trump will not be able to run in, as he will have served the maximum of two terms as president.

Paul Musgrave, associate professor of government at Georgetown University in Qatar, told Al Jazeera there are “major internal divisions within the Republican Party” over the war.

The US decision to attack Iran triggered a global fuel crisis with the closure of the Strait of Hormuz, which has cost the US taxpayer an estimated $47bn so far. This means candidates for 2028 likely need to distance themselves from the war if they have any hope of winning.

But Musgrave said hawks such as Cruz and the late Senator Lindsey Graham had, in fact, long pushed for a war on Iran. Now that they have one, “it has been a disaster internationally and domestically for them”, he said, but “they can’t walk away”. Instead, they are limited to criticising its length and execution.

Vance, however, “is trying to represent a more isolationist wing of the Republican Party, and is willing to walk away from the war and probably other commitments to win favour with a large part of the Trump base”, Musgrave said.

“This is all about positioning for 2028 and the future of the Republican Party,” he said.

John Feehery, a former Republican congressional staffer, told Al Jazeera the Iran war “was a big part” of the defeat, alongside energy prices, healthcare and corruption. The race to succeed Trump has already begun, he said, pointing to Vance and Florida Governor Ron DeSantis. Limit the money available for continuing the war, and squeeze the people running it.

Senate Democratic Leader Chuck Schumer said on Wednesday that “this war must end”, pointing to Congress’s control of funding.

“The Founding Fathers had the power of the purse as one of the ways of deterring a president who does war without the consent of the American people,” he told a news conference in Washington, DC.

Congressman Ro Khanna proposed a continuing resolution “prohibiting the financing of any combat activities of the US military in Iran”, ending the war “like we did for Vietnam”.

Musgrave said appropriations would be “a principal lever”, especially given “the havoc that has been wreaked with the defence budget by the spiralling expenses of the war in Iran”.

Feehery, meanwhile, noted that the defence budget and an extension of the debt limit would both need bipartisan support to pass.

Official hearings and investigations, over which Democrats now wield a great deal more power by dominating both chambers of Congress, could also “make the war unpopular and harass or drive from office several key players”, Musgrave said.

Secretary of Defense Pete Hegseth is also in the firing line. Outgoing Republican Senator Thom Tillis told CBS News that Hegseth would face a “reckoning” for his part in the Iran war, while Democratic Representative Jason Crow labelled the defence chief as “incompetent and corrupt”.

But Musgrave warned that the bigger fight will likely be over the Trump administration’s refusal to obey congressional spending limits. “I expect many more fights over that than even over the War Powers Act,” he said, referring to the law that requires presidents to gain Congress’s permission before launching a war overseas, but which many presidents have managed to circumvent in the past. Yes, even as diplomatic efforts and Qatar-led mediated talks continue.

On Tuesday, as Americans voted, US forces struck Iran’s Qeshm Island in the Strait of Hormuz, the first attack there since June. US officials described the strikes as “defensive”.

US media, citing officials, also reported that the military’s Central Command had prepared for strikes that could begin as early as Wednesday, when three US aircraft carriers would be in the region.

Giorgio Cafiero, CEO of Gulf State Analytics, said Trump “prides himself in leaving everyone, including the Iranians, constantly guessing”.

With the midterms behind him, “Trump may conclude that he has nothing to lose and choose to significantly escalate this crisis”, Cafiero told Al Jazeera.

Democrats “won’t even take power until January 2027”, he noted. “So perhaps Trump will see these upcoming months as a window of opportunity to act very aggressively toward Tehran.”Tehran has already promised to respond to any attacks. Diplomacy is moving in parallel.

Majed al-Ansari, a spokesperson for Qatar’s Ministry of Foreign Affairs, said Washington and Tehran “remain committed to the negotiation process”, though Iran called the latest US response to Tehran’s conditions for reopening the Strait of Hormuz “unconvincing”.

Cafiero said Doha’s mediation “can only prove successful if a willingness to compromise on core issues exists on both sides”. He added: “Israel will do all it can to play spoiler to any diplomatic arrangement that Qatar may ultimately help facilitate.”Trump told The Financial Times on election night that he had no immediate plans to order new attacks.