House Republicans are publicly cheering Trump’s Iran war. Privately, many are worried.

The vast majority of congressional Republicans are publicly supportive of President Donald Trump’s decision to launch a war on Iran. But many are harboring private misgivings about the risks to American troops and global stability — as well as their own political fortunes — should the military campaign drag on indefinitely.

Trump’s comments this week that the bombing could last “four to five weeks” or more, that he doesn’t care about public polling and that the U.S. will do “whatever” it takes to secure its objectives are among the factors that have put lawmakers on edge.

Some of the anxieties have started emerging publicly.

“The constitutional sequence is, you engage the public before you go to war unless an attack is imminent. And imminent means like, imminent — not like something that's been over a 47-year period of time,” Rep. Warren Davidson (R-Ohio), a former Army ranger, said Tuesday.

Rep. Eli Crane (R-Ariz.), a combat veteran who served in the Iraq War and has cautioned in the past against regime change efforts, called it “a very dicey, a very dynamic situation right now” on the Charlie Kirk Show Monday while also making clear he would give Trump deference.

“I hope it works out,” he added. “Military operations like this can go sideways so fast, you know, it will make your head spin.”

But a wider group of House Republicans granted anonymity to speak candidly shared deeper concerns about the strikes. All said they would stand with Trump and Speaker Mike Johnson this week to oppose a largely Democratic effort to force votes on restraining the president. But they said their support was not guaranteed over the long term.

“Most Republicans want clear objectives, clearer than they are now,” said one House Republican, who added members have pressed GOP leaders and White House officials to be more consistent in articulating the administration’s military goals.

Another was troubled by Trump’s own shifting statements on when the bombing campaign might wrap up, whether he is seeking the fall of the Islamic regime and whether ground troops might ultimately be necessary.

“Sounds a little bit like President Lyndon Johnson going into Vietnam, doesn't it?” the lawmaker said.

Trump officials and top House GOP leaders have already moved to ease potential member concerns. Johnson, for instance, said leaving a classified briefing Monday that “the operation will be wound up quickly, by God’s grace and will.”

“That is our prayer for everybody involved,” he added.

A White House memo sent to congressional Republicans Monday outlined several military objectives for the bombing campaign and said Trump should be “commended” for taking on a hostile state sponsor of terrorism.

But despite denying that Trump had acted in pursuit of regime change, the document also said the Iranian regime “would be defeated” and included other contradictory statements about the reasons for the strikes — while trying to sidestep the question of whether the strikes constituted a “war,” a word Trump himself has used.

Beyond the fears of a prolonged military engagement that could be costly in dollars and American lives, Republicans are also facing the prospect of a stock market tumble and rising gas prices that could fall hardest on vulnerable incumbents ahead of the midterms. Many of those members promised their constituents, much as Trump did, that they would not engage in endless war.

The planned Thursday vote on a bipartisan war powers resolution has surfaced some of the GOP discomfort, even as party leaders and White House officials whip members against it — including those most at risk of losing their seats.

Rep. Thomas Massie (R-Ky.), who is co-leading the war powers push with Rep. Ro Khanna (D-Calif.), pointed to the White House memo as further evidence of incoherence on the administration’s part.

“So they’re going to defeat a terrorist regime that rules a country of 90 million people, but that’s not war?” he said in an interview.

Also raising concerns in advance of the vote is Davidson, who has long railed against extended U.S. wars abroad. He said in a social media post Monday it was “troubling” that Secretary of State Marco Rubio said Monday that an imminent Israeli attack on Iran forced the U.S. to strike. He also raised concerns to reporters Tuesday about some of the administration's claims.

House Intelligence Chair Rick Crawford (R-Ark.) said in an interview Tuesday he didn’t think the war powers vote was necessary and that Trump was operating within his legal authority.

The vote, he said, was “a way for individuals to sort of register their displeasure or make a political statement.”

Even if the war powers measure is defeated, some Republicans say an effort to restrain Trump could reemerge if the conflict drags on or Trump commits ground troops to the conflict. “If we’re talking months, not weeks, then you will see another vote,” said a third House Republican who added that Trump had some “leeway” for now.

Johnson, meanwhile, is channeling any intraparty concerns about Trump’s war into another vote this week on a stalled Homeland Security spending bill — an attempt to keep the focus on Democrats’ opposition to funding for TSA, FEMA and other agencies as a department shutdown approaches the three-week mark.

He is also arguing, as he told reporters after a classified briefing Monday, that the war powers vote is “dangerous” at a moment when U.S. troops were in harm’s way and that Republicans would act to “put it down.” The strikes, Johnson added, did not need advance congressional approval because they were “defensive in nature.”

Those arguments have resonated with most House Republicans, who say they’re willing to give the president time.

“I think so far, the Pentagon seems to have a good plan,” said Rep. Jeff Crank (R-Colo.), a member of the Armed Services Committee who said he would give Trump “six weeks or … eight weeks or whatever we need to accomplish the missions that we set out.”

“The worst thing we could do is go in and then … to pull back or cut short, whatever our objectives are,” he added. “We're there. We need to get the objectives finished.”