The killing of U.S. troops in Jordan has reignited an "America First" foreign policy debate that — eight years into Donald Trump's takeover of the Republican Party — much of the GOP establishment still refuses to concede.

Why it matters: Republican hawks are urging President Biden to strike inside Iran in response to this weekend's drone attack by Iranian-backed militants. The White House hasn't ruled that out — stressing that the deadly attack "requires a response."

• Such a move could trigger exactly the kind of calamitous regional conflict that Biden has sought to avoid since Hamas' attack on Israel on Oct. 7 threw partisan alliances into chaos over the Middle East.
• Trump — who had a mixed track record on Iran and is seeking to unite the GOP ahead of a bruising 2024 campaign — has so far walked a tightrope, declining to say how he would act as commander in chief.

What they're saying: Prominent Trump supporters have focused much of their ire on the aggressive reaction from Republican hawks, casting them as part of the "military industrial complex."

• "F*cking lunatics," Tucker Carlson tweeted in response to Sens. Lindsey Graham (R-S.C.) and John Cornyn (R-Texas) calling on Biden to strike Iran’s military.
• Trump surrogate Vivek Ramaswamy blasted Graham and Nikki Haley for "giddily calling" for war: "It's disgusting & says a lot about the kind of GOP they're trying to re-create," the former presidential candidate tweeted.
• "Is there anyone you don't want to bomb?" Rep. Thomas Massie (R-Ky.), who supported Florida Gov. Ron DeSantis for president, tweeted at Graham.

The intrigue: Trump — who famously ordered the drone strike that killed Iranian Gen. Qasem Soleimani in January 2020 — has been far more circumspect.

• Trump responded to this weekend's attack by claiming that it "would NEVER have happened" if he were president — and blaming Biden for both Oct. 7 and the war in Ukraine.
• Iranian-backed militias in Iraq continued to target U.S. troops in the nine months after the Soleimani killing, though the attacks were not "particularly lethal," according to one top general at the time.

What to watch: Trump stacked his top foreign policy posts with Iran hawks during his presidency, and he boasted Sunday that his "maximum pressure" sanctions campaign left Iran "weak, broke, and totally under control."

• But given the growing power of isolationists in the Republican Party, Trump's Cabinet likely would look very different in a second term.
• What's less clear is how the likes of Haley, Graham, Sen. Tom Cotton (R-Ark.) and others fit into an "America First" GOP that reviles their foreign policy views.