The failure of negotiations to end the US war with Iran has unleashed a barrage of starkly partisan political responses, with leading Republicans making hawkish calls for Donald Trump to “finish the job” while top Democrats warned that it would be disastrous for the president to resume hostilities.

The former UN ambassador during Trump’s first presidency, Nikki Haley, led the Republican charge. She told CNN’s State of the Union on Sunday that the current two-week ceasefire was a test of nerves.

“This is like a game of chicken,” she said. “It’s who caves first. The Iranian regime is hoping that Trump will cave. Today, he showed he’s not.”

Haley was alluding to Trump’s threat, made hours after marathon peace talks in Pakistan ended without result, that the US military would blockade the strait of Hormuz to prevent Iran profiting from its control of the narrow shipping passage. She encouraged Trump to “go after Iran where it hurts”, adding that what would “really bring Iran to its knees is to go after it economically”.

Speaking on ABC’s This Week, US senator Ron Johnson – a Wisconsin Republican – also urged Trump to take a hard line. He advocated the total removal of the Iranian regime, admitting that the task “could be longer term”.

“We have to finish the job,” he said. “We will not have won until we have completely defanged the Iranian regime.”

A top priority for Republican war hawks is to prevent Iran ever acquiring nuclear weapons by seizing its supplies of enriched uranium. Haley gave a rosy appraisal of how that could be accomplished.

The US could launch a relatively small and quick special forces operation to grab the country’s stash of enriched uranium, she told CNN.

“This is a special forces mission,” she said. “It would take about a week to 10 days to get done. They know how to do it.”

US senator Mark Warner of Virginia, who is the top Democrat on the Senate’s intelligence committee, fiercely rebutted Haley’s bellicose remarks. He told State of the Union that attempting to seize Iran’s 1,000lb canisters of highly volatile enriched uranium would be “very, very dangerous”.

“It would take 10,000 troops on the ground guarding a perimeter,” Warner said. “We’d have to send special operators in, and the Iranians could then bomb their own facility, potentially trapping our troops.”

Warner’s fellow Democratic senator from Virginia, Tim Kaine, told This Week that he would be pressing again for a war motion in the Senate in the coming days to try to stop Trump returning to full-scale hostilities. He argued that even an imperfect ceasefire would be preferable to resuming war.

“Returning to full war will just compound the suffering of American troops and the American citizenry who are suffering under a devastated economy because of what Donald Trump has done,” Kaine said.

Kaine, who sits on both the Senate armed services and foreign relations committees, added: “We shouldn’t be in this war to begin with. Donald Trump launched this war without the support of allies, the American public, or Congress.”

Beyond Capitol Hill, Zohran Mamdani, the Democratic mayor of New York City, reiterated his passionate opposition to the US-Israel war with Iran. Interviewed by Al Jazeera, he laid out what he called the moral case against the conflict.

He said the fighting was deeply unpopular among Americans and was utilizing “tens of billions of dollars to kill people, money that could otherwise be used to make life easier for people”.

Mamdani quoted the line by the late rapper Tupac Shakur from his 1993 song, Keep Ya Head Up: “They got money for wars, but can’t feed the poor.”