US lawmakers may soon be forced to confront a central question raised by Democrats and a small number of Republican critics: has the Trump administration launched military action against Iran without proper legal authorisation from Congress?

Reporting from Washington DC, Al Jazeera’s Rosiland Jordan says the Senate could take up a resolution on Wednesday that would require Congress to decide whether to formally consent to the ongoing operation. The House of Representatives has also been seeking to schedule a similar measure.

However, the political maths remains uncertain. Even if the resolutions reach the floor, supporters would need enough votes in both chambers to restrain or halt the operation — something that looks difficult given many Republicans have already argued the strikes are lawful.

Republicans also hold majorities in both the Senate and the House, making it harder for opponents to force through binding limits on the administration’s actions.