Opposition is growing in the US Congress to any potential military action against Iran, with lawmakers warning that such intervention could backfire and would violate the Constitution.
Read More: US senate blocks bid to limit Trump’s Iran war powers
Senior Democrats and Republicans alike have questioned the Trump administration’s threats of military action amid widespread protests in Iran over economic hardship and calls for regime change. Lawmakers cautioned that using force to support protesters could undermine the very movement the US intends to help.
“The US should not engage in any military action within Iran unless Congress authorizes it.”
Democratic Senator from Virginia @SenTimKaine speaking with @CNN @NewsCentralCNN about protests in Iran.
Via #StudiGo mobile studio pic.twitter.com/LOiGnkCL0m
— StudiGo (@StudiGo_LLC) January 12, 2026
Republican Senator Rand Paul and Representatives Thomas Massie and Marjorie Taylor Greene emphasised that the United States should focus on domestic priorities rather than engaging in “endless foreign wars.” Paul highlighted the risk that military action could unite Iranians behind their government, including those currently protesting, and warned of inevitable civilian casualties. “Bombing is not the answer,” he said, questioning how the US could protect protesters if strikes were carried out.
Democratic Senator Mark Warner, ranking member of the Senate Intelligence Committee, cited historical consequences of US intervention in Iran, including the 1953 CIA-backed coup, which ultimately contributed to the rise of the ayatollahs in the 1970s. Warner cautioned that military action today could similarly strengthen, rather than weaken, the current Iranian leadership.
Legislative measures have also been proposed. Senators Bernie Sanders and Tim Kaine introduced a bill to bar federal funds for military action against Iran unless explicitly authorised by Congress. The measure, co-sponsored by Senators Elizabeth Warren, Jeff Merkley, and Chris Van Hollen, underlines that only Congress has the constitutional authority to declare war under Article I, Section 8. The senators stressed that no such declaration or statutory authorisation currently exists.
Read More: Congress urged to halt Trump’s military actions against Iran amid
The bipartisan pushback highlights growing scepticism in Washington over military intervention in Iran, reflecting concerns over constitutional authority, potential civilian harm, and the unintended consequences of foreign involvement in domestic uprisings.