WASHINGTON (AP) — Senate Democrats have rallied the 34 votes they need to keep the Iran nuclear deal alive in Congress, handing the President a major foreign policy victory.

Sen. Barbara Mikulski of Maryland became the crucial 34th vote Wednesday morning, declaring the agreement is the best way to curb Iran's nuclear ambitions.

Congress is to vote later this month on a resolution disapproving the deal, which is unanimously opposed by Republicans, who call it a dangerous giveaway to Iran.

Obama has vowed to veto the resolution if it passes. It would take 34 votes to uphold his veto, and Democrats now have those in hand.

The agreement — signed by Iran, the U.S. and five other world powers — seeks to dismantle Iran's nuclear program in exchange for billions of dollars in relief from sanctions.