The longer U.S. President Donald Trump’s war against Iran continues, the likelier it becomes that he’ll have to turn to Congress for extra military funding. And if that happens, he is expected to encounter a firm wall of Democratic opposition.
“There is a very solid group of Democrats whose position is going to be that the administration has gotten $1 trillion for the Pentagon and more than enough extra funds in the Big Beautiful Bill and has yet to give any information on how the money is being spent,” said Jeremy Ben-Ami, president of J Street, a liberal pro-Israel U.S. lobbying group, whose organization held its annual Capitol Hill outreach day last week. “So, if it needs extra money now … the money is there, they just need to reprogram it.”
The longer U.S. President Donald Trump’s war against Iran continues, the likelier it becomes that he’ll have to turn to Congress for extra military funding. And if that happens, he is expected to encounter a firm wall of Democratic opposition.
“There is a very solid group of Democrats whose position is going to be that the administration has gotten $1 trillion for the Pentagon and more than enough extra funds in the Big Beautiful Bill and has yet to give any information on how the money is being spent,” said Jeremy Ben-Ami, president of J Street, a liberal pro-Israel U.S. lobbying group, whose organization held its annual Capitol Hill outreach day last week. “So, if it needs extra money now … the money is there, they just need to reprogram it.”
Ben-Ami was referencing the $1 trillion that the Defense Department received in the last year from Capitol Hill, including fiscal 2026 appropriations as well as an extra $153 billion in military spending provided through a Republican budget and policy bill.
Concrete details are scarce on the timing of a potential Trump administration emergency war spending request or for how much, though the figure of $50 billion has been circulating around Capitol Hill.
Since the United States began striking Iran on Feb. 28, the president and his top defense officials have offered changing predictions for how long the fighting against Tehran will continue, ranging from days to about a month. Yet U.S. Central Command reportedly has asked for extra military intelligence officers to be transferred to its Tampa, Florida, headquarters to support strikes against Iran up until the end of September.
The U.S. Defense Department hasn’t yet disclosed how much the war against Iran has cost or is projected to cost. Independent budget analysts with the right-leaning American Enterprise Institute (AEI) estimate that war-related costs thus far are roughly $11.6 billion, including expenses related to the positioning and operation of U.S. naval and air assets in the Gulf region, used interceptors and munitions, and special hazard pay for troops.
“The department doesn’t want to submit a supplemental until they know with some level of certainty what the cost is going to be for the year, because you don’t want to have to go back to Congress and ask again,” said AEI senior fellow Elaine McCusker, who was the comptroller for the Defense Department during the first Trump administration.
She has been tabulating the incremental costs of the Iran war using publicly available information, including statistics shared during Defense Department briefings as well as her own informed assumptions on what aircraft, munitions, and interceptors have likely been used based on what the U.S. military has targeted in Iran. Her team’s estimate does not yet account for battle damage sustained to U.S. bases and defense equipment.
For now, congressional Democrats appear unified on how they would respond to a funding request. In addition to the $153 billion in extra defense spending provided to the U.S. military last year, the Republican reconciliation bill also included an extra $191 billion for the Homeland Security Department, which has come under heavy Democratic criticism amid the department’s harsh and deadly crackdown against immigrants and U.S. citizens alike. All told, that’s $344 billion in extra spending that Democrats didn’t support when it was passed last year but are now arguing should be reappropriated for any Iran war-related spending needs prior to taxpayers being asked for new funds.
Votes in the Senate and the House last week showed that Democrats in both chambers are nearly united in opposing Trump’s unauthorized war against Iran. But it’s possible Democratic cohesion could be challenged once they see an actual spending request, particularly if it includes funding for issues they are more supportive of such as humanitarian funding or even new security assistance for Ukraine. A sharp uptick in U.S. troop casualties could also impact Democratic thinking.
“If you support the troops, then you should be voting against funding this war so that we get our troops out of harm’s way,” said Democratic Sen. Chris Murphy in a Sunday interview with CNN. “Virtually nothing good happened from sending thousands of Americans to die inside Iraq in the 2000s and if we don’t learn that lesson, then shame on every single one of us.”
Ed Meier, the former associate director for national security in the White House Office of Management and Budget during the Biden administration, said that Trump and the Defense Department have done little to convince lawmakers that there are clear objectives and an actionable plan for winning the Iran war.
“At the start of a war, you really need to define what your strategic objectives are, what are the conditions for how you define success, what the post-conflict plans are, and those pieces are essential to really understanding the full scope and scale of what a war is going to be,” Meier said. “I don’t see how you can estimate the cost of a war without clearly defining the objectives and having a clear understanding of what success looks like and defining what that looks like from the outset.”
But McCusker believes it would be shortsighted for Democrats to insist that funds from the partisan Republican spending bill be spent first before any new emergency funding is provided for the Iran war.
“If you start using unobligated procurement money for current operations,” that undermines efforts by the U.S. government to send positive demand signals to the defense industry about the reliability of U.S. spending, she said.
Stoking the U.S. defense industry to make the long-term investments necessary to expand its production capacity, particularly for things like advanced munitions and interceptors, is a congressional bipartisan priority amid strong national and allied demand to replenish depleted ammunition stockpiles that have been used in recent fighting in Ukraine and the Middle East and may be needed for future possible conflicts in the Indo-Pacific.
It’s unclear how much military funding from the Republican spending bill remains unobligated, but the number is easily in the billions. According to recent Defense Department documents, billions of dollars in funding for missile defense and drone production has yet to be disbursed.
“I believe that our troops have been asked to complete a mission and they are forward-deployed in harm’s way and we need to make sure they have the support they need to safely carry out their mission and come home, and I believe the funds are available to do just that through the One Big Beautiful Bill,” Meier said.
While the administration is believed to have the authority to reprogram the Defense Department funding in the Republican reconciliation bill for Iran war-related needs, the White House would likely have to obtain congressional approval to reappropriate the billions in funding provided to the Department of Homeland Security, according to budget experts.
