Republicans who control Congress are preparing for a contentious debate over how to pay for the U.S. military campaign against Iran, as independent estimates put the conflict’s cost to date near $30 billion and lawmakers warn the 1973 War Powers Resolution’s 60-day clock is approaching.
The growing price tag of the U.S. military campaign against Iran is setting up a politically fraught funding fight for Republicans as Congress prepares to return from recess.
One estimate from the Center for Strategic and International Studies (CSIS) has put the cost of the war so far at nearly $30 billion, though the White House has not released a detailed public accounting of the conflict’s expenses. Under the 1973 War Powers Resolution, military operations generally must end after 60 days without congressional approval, though a president can invoke a 30-day extension.
In recent days, a number of Republican lawmakers have publicly raised concerns about the duration of the operation, congressional oversight and the prospect of a wider escalation.
Sen. Susan Collins, R-Maine, criticized President Trump’s “incendiary” remarks about the war and said she would oppose sending ground troops to Iran or extending the conflict beyond 60 days without congressional approval unless circumstances changed significantly. Collins said congressional authorization would be required if the administration deploys “boots on the ground” or if hostilities extend beyond the 60-day window.
Sen. John Curtis, R-Utah, has said he would not support military action beyond 60 days without congressional approval. Other Republicans, including Sens. Thom Tillis of North Carolina and Todd Young of Indiana, have also urged limits and oversight. Sen. Lisa Murkowski, R-Alaska, has called for more transparency from the administration, saying lawmakers were learning key details through news reports rather than formal briefings.
A costly war and uncertain next request
Republican leaders could pursue new war funding through a supplemental appropriations bill or attempt to route it through the budget reconciliation process, which can allow the Senate to pass certain fiscal legislation without Democratic votes.
Mark Cancian, a senior adviser at CSIS who has worked on cost estimates for the conflict, said there has been discussion of a supplemental funding request in the range of $80 billion to $100 billion to cover the war’s costs. He cited major drivers including the heavy use of expensive weapons systems and damage to U.S. aircraft and infrastructure.
The Washington Post has reported that the U.S. has fired more than 850 Tomahawk cruise missiles in the conflict, a level Cancian said would be unprecedented for a U.S. war. Using a unit cost of about $3.6 million per Tomahawk, Cancian said the missile expenditures alone are a significant contributor to the total.
Cancian also said the U.S. may have lost an estimated $1 billion in military jets and other aircraft. He said a high-profile rescue mission for two U.S. airmen in Iran—an operation that involved the loss of several aircraft—may have cost roughly $500 million.
The White House, meanwhile, has asked Congress to approve roughly $1.5 trillion for defense in fiscal year 2027, though it has not specified what portion, if any, would be directly tied to the Iran campaign.
With narrow Republican majorities in both chambers, party leaders face additional pressure from members who oppose the war outright. Sen. Rand Paul of Kentucky and Rep. Thomas Massie of Kentucky are among the fiscal conservatives expected to resist new funding.
Democrats push war powers votes and highlight economic effects
Democrats are expected to keep pressing for votes aimed at limiting the president’s war powers. House Democrats recently attempted to force a vote to restrict Trump’s authority over the Iran operation, and additional votes are expected in both chambers.
Senate Minority Leader Chuck Schumer, D-N.Y., has argued that no president should take the country to war without Congress. House Minority Leader Hakeem Jeffries, D-N.Y., has sought to tie the war to rising costs facing households, including higher fuel prices.
Beyond direct federal spending, economists and analysts say the conflict is also showing up in household costs. Roger Pielke Jr., a senior fellow at the American Enterprise Institute, estimated that higher gasoline and diesel prices through April 1 could cost Americans about $12.1 billion—roughly $92 per household—and said higher jet-fuel costs in the same period could add another $2.2 billion through increased airfares. He also estimated that U.S. farmers could pay an additional $131 million in fertilizer costs, which could eventually be passed on to consumers.
Even as Democrats try to use the issue to sharpen their political message, the party has shown divisions on war powers votes. Several Democrats—including Sen. John Fetterman of Pennsylvania and Reps. Henry Cuellar of Texas, Juan Vargas of California and Jared Golden of Maine—voted last month against a measure to limit the president’s Iran war authority.
