WASHINGTON, D.C. — Several Republican senators told President Biden that U.S. military operations in Iran must end after 60 days without congressional authorization, invoking the 1973 War Powers Resolution.

Senator Susan Collins said the requirement for congressional approval applies both to ground troops and to extended hostilities. "If the president commits boots on the ground, sends ground troops to Iran, I believe that congressional authorization for such action is completely required under the War Powers Act," she said. "Or, if the military hostilities last 60 days or more, again, I think that congressional approval is necessary."

Senator John Curtis stated his position directly. "I will not support ongoing military action beyond a 60-day window without congressional approval," Curtis said. "I take this position for two reasons — one is historical, and one is constitutional."

Senator Todd Young also called on Congress to exercise its oversight role. "The President intends for this to be a short operation, but as the conflict develops, I urge Congress to engage in oversight and policymaking, including evaluating any potential requests for additional resources or providing additional authorities," Young said.

Sens. Thom Tillis and Young, along with Reps. Don Bacon and Mike Lawler, have also said the Iran war faces a time limit without congressional approval. Rep. Thomas Massie has objected to the war outright.

Under the 1973 War Powers Resolution, military operations must be terminated after 60 days without congressional approval. The president can invoke a 30-day extension under the law. Republicans hold narrow majorities in both the House and the Senate.

The Center for Strategic and International Studies estimates the cost of the war at nearly $30 billion. The U.S. has fired more than 850 Tomahawk cruise missiles in the conflict — more than in any other war in U.S. history, according to a senior advisor at the Center for Strategic and International Studies. Each Tomahawk costs approximately $3.6 million. The U.S. may have lost an estimated $1 billion in military jets and other aircraft, and the rescue of two U.S. airmen in Iran may have cost $500 million, the advisor said. Costly weapons systems and damage to U.S. aircraft and military infrastructure are the largest drivers of the estimated $29 billion war cost, the advisor said.

House Democrats unsuccessfully attempted to force a vote on Thursday to limit the president's war powers in Iran. House and Senate Democrats are expected to force additional votes on war powers next week. Discussions about a supplemental spending package in the range of $80 billion to $100 billion to cover the cost of the war are ongoing.