President Obama and Democratic Senator Chuck Schumer. Photo: Pete Souza/White House.

New York Senator Chuck Schumer escalated his confrontation with President Obama over the Iran nuclear deal on Friday by promising a vote to override an expected Presidential veto of congressional legislation seeking to block the agreement.

“Yes, the Senator would be prepared to vote to override a Presidential veto of the bill,” a representative from the leading Democrat’s office told The Algemeiner.

Schumer’s pledge comes soon after announcing his opposition to the deal late Thursday night in a lengthy and detailed critique of the controversial agreement.

On Thursday, Schumer summed up his decision saying it was guided by his belief that “Iran will not change” and therefore, under the agreement, the country “will be able to achieve its dual goals of eliminating sanctions while ultimately retaining its nuclear and non-nuclear power.”

Asked if he would work to lobby other senators and members of Congress to oppose the deal, the third highest ranking Democrat claimed that his influence was limited.

“There are some who believe that I can force my colleagues to vote my way,” he said. “While I will certainly share my view and try to persuade them that the vote to disapprove is the right one, in my experience with matters of conscience and great consequence like this, each member ultimately comes to their own conclusion.”

While Schumer’s stance has been widely praised by opponents of the Iran agreement, some were more skeptical of the Senator’s intent and suggested that behind-the-scenes deal-making had influenced his decision.

“If Schumer does, in fact, come out against the deal, it might mean that the future Dem leader understands that Obama’s victory is secure,” tweeted The Atlantic columnist Jeffrey Goldberg.

Since the Iran deal was announced on July 14, President Obama has made it clear that he would veto any legislative effort to stifle the agreement through the Iran Nuclear Agreement Review Act, which grants Congress 60 days to approve or reject the deal. Opponents of the deal have been working hard to secure a veto-proof majority in the House and Senate, and many consider Schumer’s stance to be crucial to their success.

Earlier on Thursday, Schumer’s colleague Senator Kirsten Gillibrand announced her support for the deal while calling it “imperfect,” and New York Congressman Eliot Engel voiced his opposition.

Many Jewish groups in the U.S. have been actively lobbying against the deal, saying it threatens the United States and puts Israel in unacceptable danger.