President Obama needs 34 votes in the Senate to prevent Republicans from killing the Iran nuclear deal, and it’s beginning to look like he’s going to get them as Sen. Bob Casey throws in his support.

Sen. Bob Casey of Pennsylvania will back the Iran nuclear deal, becoming the 32nd Senate Democrat to pledge support for the agreement, which puts the White House within striking distance of the votes it needs to ensure the deal survives in Congress.

Casey announced his decision Tuesday afternoon after weeks of mulling the much-disputed deal with the longtime U.S. nemesis. His statement is 17 pages long, including more than a page of citations, and it goes through a range of concerns and objections raised by skeptics of the deal before essentially rebutting each one.

“I firmly believe that effective implementation of the [agreement], bolstered by other U.S. policies, including a strong deterrence policy of the U.S. and our partners, will be in our national security interest,” Casey writes. “This agreement will substantially constrain the Iranian nuclear program for its duration, and compared with all realistic alternatives, it is the best option available to us at this time.”