Sens. Chris Coons and Bob Casey announced their support for the deal Tuesday.

WASHINGTON — Sen. Chris Coons (D-Del.) came out in favor of the Iran nuclear deal on Tuesday, calling his decision a “very hard choice” and putting the Obama administration within one vote of a victory.

Coons is the 33rd Senate Democrat to come out in favor of the deal, which curbs Iran’s nuclear program in exchange for some sanctions relief provided by President Barack Obama. The president only needs one more Senate Democrat in support of the deal to reach 34, the number needed to sustain his veto on a resolution of disapproval. 

“I will support this agreement because 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,” Coons said during a speech at the University of Delaware. “The alternative, to me, is a scenario of uncertainty and isolation.”

Senate Majority Leader Mitch McConnell (R-Ky.) could bring up the resolution of disapproval for a Senate vote as early as the second week of September, when the upper chamber returns from its summer recess. 

Coons said he plans to “vote against any measures to disapprove it in Congress.”

He was careful to note that it is not a “perfect” deal, but the “most credible” option to contain an “existential threat.” source