A vote to block President Barack Obama’s Iran nuclear deal failed on Thursday as Democrats handed him a welcome foreign policy victory.

A vote to block President Barack Obama’s Iran nuclear deal failed on Thursday as Democrats handed him a welcome foreign policy victory.

As expected, US senators fell two votes shy of the 60 needed to advance a resolution disapproving of the international accord, meaning the legislation aimed at sabotaging the deal is essentially dead.

"The Senate has spoken with a clarion voice and declared that the historic agreement to prevent Iran from obtaining a nuclear weapon will stand," Senate Minority Leader Harry Reid said after Democrats cleared the way for the accord.

Obama hailed the vote as "a victory for diplomacy, for American national security, and for the safety and security of the world."

"Going forward, we will turn to the critical work of implementing and verifying this deal so that Iran cannot pursue a nuclear weapon, while pursuing a foreign policy that leaves our country -- and the world -- a safer place."

Four Democrats including Chuck Schumer, the party's likely Senate leader in 2017 once Reid retires, opposed the accord, joining all 54 Republicans.

But the 58-42 vote in favor of disapproval was not enough to get over the 60-vote procedural hurdle.

The result effectively assures that the deal will go into force while sparing Obama the embarrassment of having to use his veto pen against a disapproval resolution.

But Republicans, who unanimously oppose the accord, vowed to keep fighting, with House Speaker John Boehner insisting "this debate is far from over."

Boehner said House Republicans will "use every tool at our disposal to stop, slow and delay this agreement from being fully implemented," including suing the president to prevent him from carrying out the Iran accord.

"That is an option that is very possible," Boehner told reporters Thursday.