Senate Minority Leader Harry Reid has announced he will support the Iran nuclear deal and will do "everything in my power to ensure that it stands."

"One of the most important national security challenges of our generation is stopping Iran from getting a nuclear weapon, a goal that is critical to the national security of the United States, the State of Israel and the world. After years of study and months of careful review of the Joint Comprehensive Plan of Action and its predecessor agreement, I support this agreement because I believe it is the best path to stop Iran from obtaining a nuclear weapon," Reid said in a statement.

Reid spoke with the Washington Post on Sunday, giving the unpopular deal a "forceful endorsement."

The Nevada Democrat is the 27th Senate Democrat to endorse the deal, while only two senators, Senator Chuck Schumer (D-NY) and Senator Robert Menendez (D), have publicly opposed the deal.

Reid said he is "cautiously optimistic" that he could prevent an override of Obama's veto on a resolution that opposes the deal. The WaPo writes, "An override would require opponents mustering 13 Democrats to join all 54 Republicans in opposition to the president."

"This is the best way, the only way, to keep Iran from getting a nuclear weapon," Reid said Sunday.

There are still 17 Democrats who have not announced how they will vote on a resolution opposing the deal. Both chambers have majority support to reject Obama's deal, the real issue is whether the chambers can support Obama's veto.