WASHINGTON – Sen. Chris Coons (D., Del.) endorsed the international nuclear deal with Iran Tuesday, just hours after Sen. Bob Casey (D., Pa.) announced his support. Together, the two put the deal on the brink of having enough support to withstand Congressional criticism.

Casey and Coons were the 32d and 33d senators to endorse the agreement, one shy of the number President Obama needs to sustain a veto blocking a potential Congressional resolution to reject the deal. If the president can corral 41 Senate votes, supporters can block the disapproving resolution altogether, and avoid the need for a veto.

Coons expressed deep concerns about the international deal – spending much of a 37-minute speech at the University of Delaware outlining its flaws – but said he ultimately saw it as "the most credible opportunity now" to constrain Iran, and that the U.S. risked losing its influence if Congress walked away from a hard-won pact.

"In a very hard choice," between either rejecting the agreement for its weaknesses "or a path that accepts the positives of this deal and attempts to manage and minimize the short and long term consequences of its flaws, I choose the latter," said Coons, a member of the Senate Foreign Relations Committee. He first revealed his decision Tuesday in an interview with the Washington Post.

"It puts us on a known path of limiting Iran's nuclear program for the next 15 years with the full support of the international community. The alternative, to me, is a scenario of uncertainty and likely isolation," he said in his speech.

Both Coons and Casey were seen as key swing votes, representing states with significant Jewish populations and where opponents and supporters had heavily advertised to try to sway lawmakers. Both senators described lengthy deliberations and expected harsh reactions from those who see this agreement as an existential threat to Israel. Coons acknowledge many concerns about the deal.

"Frankly, this is not the agreement I had hoped for," he said, pointing out that the agreement will freeze – but not dismantle – Iran's nuclear program and worrying about the continued anti-American and anti-Israel rhetoric from Tehran.

But he said the deal will push Iran further away from acquiring a bomb for the next 15 years and give the U.S. and its allies more information about the country's nuclear program if military action is needed. Coons urged the administration to take a tough stand on any violations and to hold out the possibility of using military force. He said he got a letter from the Obama administration committing to strengthening Israel's defense capabilities, among other steps.

"I support this deal with my eyes wide open, aware of the deal's flaws as well as its potential," he said.

Sen. Tom Carper (D., Del.) has also announced his support for the deal while Sens. Pat Toomey (R., Pa.) and Bob Menendez (D., N.J.) oppose it. Sen. Cory Booker (D., N.J.) has not announced his decision.

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