Democrats in the US Senate have blocked a Republican resolution to reject the nuclear agreement between Iran and the P5+1 group of countries, delivering President Barack Obama a landmark foreign policy victory.

Republican senators, who only a few months earlier vowed to muster 67 votes to override a presidential veto, fell two votes short on Thursday of the 60 needed in the 100-member chamber to advance a resolution disapproving of the Vienna nuclear accord.

This means the legislation aimed at sabotaging the historic agreement is essentially dead, and that the deal will now take effect without a veto showdown between the Republican-controlled Congress and the Obama administration.

GOP refuses to concede defeat

US Senate Majority Whip John Cornyn

However, Republicans refused to concede defeat on Thursday and said the Senate will vote on the Iran deal next week one more time.

Senate Majority Leader Mitch McConnell said the Senate will vote against the nuclear agreement again before the September 17 deadline to see “if any folks want to change their minds.”

McConnell, nonetheless, admitted that it seemed there was no way to block the nuclear accord in Congress.

And his deputy, Senate Majority Whip John Cornyn told reporters, “It will be all Iran next week.”

“There are going to be more votes,” he said. “There will be other opportunities for people to change their mind next week, hopefully after they hear from their constituents."

Forty-two of Democratic senators voted on Thursday to filibuster the Republican disapproval resolution and ensured sanctions are lifted on Iran in the spring of next year.

Four Dems vote against Vienna accord

Democratic Senators Chuck Schumer (right) and Robert Menendez

Four Democratic senators voted against the Joint Comprehensive Plan of Action (JCPOA) reached between Iran and the P5+1 group of countries in July in Vienna, Austria. They are Chuck Schumer of New York, Ben Cardin of Maryland, Senator Joe Manchin of West Virginia and Bob Menendez of New Jersey

The Obama administration has gained this resounding victory over its opponents, despite the Israel lobby’s massive campaign to defeat the historic nuclear agreement, reached between Iran and the P5+1 -- the US, Britain, Russia, China, France, and Germany -- in Vienna in mid-July.

The American-Israeli Public Affairs Committee (AIPAC) has deployed hundreds of lobbyists on the US Capitol to try to convince lawmakers to vote against the agreement.

According to reports, AIPAC and other pro-Israel lobbying groups have spent at least $40 million on television commercials and other propaganda material to inform the public “about the dangers of the proposed Iran deal.”