US Democratic lawmakers are considering using their control over federal spending to block further funding for President Donald Trump’s war on Iran, as pressure mounts within the party to bring Trump's "war of choice" to an end.

The issue is expected to feature prominently in negotiations over a federal spending bill ahead of a December 11 deadline, when Congress must approve fresh funding to prevent a government shutdown.

Democrats, who are set to take control of both chambers of Congress in January, face mounting calls from within their ranks to make any year-end funding agreement conditional on halting financial support for the military campaign against Iran.

Connecticut Representative Rosa DeLauro, the Democrats’ top member on the House Appropriations Committee, said on Thursday that the party would not support further funding for the war.

“Democrats will absolutely not fund Trump’s war of choice with Iran that has increased costs on American families and made us less safe,” the Politico reported.

House Minority Leader Hakeem Jeffries, who is expected to become speaker when Democrats assume control of the chamber, said party leaders would discuss the issue with DeLauro, describing the war on Iran as "reckless and costly."

Jeffries also said the midterm election results reflected public demands for accountability and an end to the war.

The prospect of a funding confrontation has also gained support from prominent Democrats seen as potential contenders for the party’s 2028 presidential nomination.

California Representative Ro Khanna called on Democrats to use their congressional majority to end the war, comparing the proposed move to the 1973 congressional action that cut off funding for US military operations in Southeast Asia during the Vietnam War.

Khanna also urged lawmakers to support a temporary funding measure in December that would prohibit the use of federal money for any US military combat operations in Iran.

Illinois Governor JB Pritzker, another potential presidential contender, has similarly urged Democrats not to back down from efforts to block war funding.

In an interview with The Bulwark earlier this week, Pritzker called on the party to stand firm, arguing that Democrats should no longer be reluctant to challenge the Trump administration over the war.

Meanwhile, Senate Minority Leader Chuck Schumer, who is expected to lead the Democratic majority next year, said he was working with Washington Senator Patty Murray, the party's leading member on the Senate Appropriations Committee, to reach an agreement on government funding before the December deadline.

Murray also linked the Democrats' electoral gains to public opposition to the war, saying voters had delivered a clear message in favor of ending the war on Iran.

Schumer pointed to Congress's constitutional authority over federal spending as a means of restraining the president's military actions.

Speaking at a news conference on Wednesday, he said Congress would use its control over the purse strings to end a war being waged without public consent.

Fuel price hikes from war on Iran squeeze US households ahead of midterms

Gasoline prices in the US are up $1 per gallon compared with levels before the aggression was launched in February.

The December 11 funding deadline could offer Democrats an early opportunity to challenge Trump's war policy, although a standoff over military spending could also trigger another government shutdown and complicate the party's legislative priorities as it prepares to take control of Congress.

Democrats will face opposition from the White House and Republican lawmakers, leaving questions over whether they can muster sufficient support to block further federal funding for the military aggression.

The Trump administration, meanwhile, has pushed back against growing criticism of the war on Iran.

US War Secretary Pete Hegseth has stepped up attacks on lawmakers questioning the objectives, financial burden and legal basis of the military offensive. However, he is himself facing mounting criticism from both Democrats and Republicans over his role in persuading Trump to launch the war.

Republican lawmakers have particularly challenged Hegseth's repeated assurances that the United States would secure a swift victory. Hegseth has also come under fire for portraying the US military's setbacks as successes.

Incoming Democratic lawmakers have pledged to investigate Hegseth's statements and scrutinize the Pentagon's wartime decision-making. They have also raised the prospect of cutting military funding and seeking his removal from office.

"I'm going after Pete Hegseth. Not only is he incompetent and corrupt, he's undermining our national security and the safety of our troops," Representative Jason Crow, a Democrat serving on the House Armed Services Committee, said.