The U.S. Senate is set to vote Wednesday on a war powers resolution that would require congressional authorization before President Donald Trump can continue military strikes against Iran. The measure, led by Democratic Sen. Tim Kaine of Virginia and co-sponsored by Republican Sen. Rand Paul of Kentucky, would direct the removal of U.S. armed forces from hostilities against Iran not authorized by Congress. The vote comes five days after Trump launched a surprise military attack on Iran last Saturday without seeking congressional approval.

The resolution faces steep odds in the Republican-controlled Senate, where Democrats hold 47 seats and need a simple majority to advance the measure. Democratic Sen. John Fetterman of Pennsylvania has pledged to vote against the resolution, meaning it would require at least four Republican votes beyond Paul's to pass. Even if it cleared both chambers, Trump could veto the measure, and Democrats lack the two-thirds majorities in both houses needed to override.

Senate Minority Leader Chuck Schumer said Tuesday that the operation lacks clear objectives and called it a war of choice. Democratic Sens. Chris Murphy of Connecticut and Cory Booker of New Jersey said administration officials acknowledged in a classified briefing that the operation is open-ended, that more American casualties are expected, and that ground troops have not been ruled out. Secretary of State Marco Rubio, speaking at the Capitol Tuesday, said the administration does not intend to put American troops in harm's way, though six U.S. military members were killed over the weekend in a drone attack. Trump has said the operation is projected to last four to five weeks but indicated the U.S. has the capability to sustain it longer.

The conflict is already triggering wider regional escalation. Israel launched a new ground incursion into southern Lebanon on Tuesday and conducted consecutive days of airstrikes on Beirut's southern suburbs, targeting what it described as Hezbollah command centers and weapons storage facilities. A senior Hezbollah official responded that the group had no option but to return to resistance, declaring that the era of patience had ended. The Lebanese army withdrew from at least seven forward operating positions along the Israeli border amid the intensifying strikes.

Kaine, who led a similar war powers effort in June that failed, said the vote serves the purpose of forcing lawmakers onto the record on a war that directly affects U.S. military personnel. The Senate and House votes represent the most significant congressional challenge yet to Trump's authority over the Iran campaign, and their outcomes will signal how much latitude Republicans are willing to grant the administration as the conflict expands with no defined exit strategy.