Sen. Bob Menendez of New Jersey, a key Democrat in the upper chamber, announced his opposition to the nuclear deal with Iran today, becoming the second Senate Democrat to do so.

“I have looked into my own soul, and my devotion to principle may once again lead me to an unpopular course, but if Iran is to acquire a nuclear bomb, it will not have my name on it,” Menendez said.

The New Jersey senator serves as one of the senior members of the Foreign Relations Committee and has spoken out against the nuclear agreement in the past, although he has not made a definitive statement about how he will vote. Menendez previously criticized the deal for preserving the Middle Eastern country’s nuclear program, rather than ending it completely, and has advocated for continuing sanctions on Tehran.

Under the negotiated deal, the United States and five world powers agreed to relieve Iran of its nuclear-related sanctions, unfreezing what experts estimate to be more than $100 billion in assets.

“I’m concerned the redlines we drew have turned into green lights; that Iran will be required only to limit rather than eliminate its nuclear program, while the international community will be required to lift the sanctions, and that it doesn’t provide for anytime-any-place inspections of suspected sites,” he said in a statement last month.

In his speech at the Seton Hall School of Diplomacy and International Relations, Menendez committed not only to voting against the deal when the Senate returns next month, but also to voting to override a presidential veto.

“We want the right deal, and a deal that does nothing more than delay the inevitable is not a deal we are willing to make,” Menendez said.

The New Jersey senator is the second Senate Democrat to come out in opposition to the deal, following Sen. Chuck Schumer of New York, who said earlier this month he would vote against the agreement. Sen. Jeff Flake, R-Ariz., who had spoken with the White House about the nuclear agreement before announcing his decision, came out in opposition last week.

Had he supported the deal, Flake likely would’ve been the lone Republican to do so.

The Obama administration has been working to drum up Democratic support for the nuclear deal with Iran, with Obama reportedly phoning congressional Democrats from a vacation home in Martha’s Vineyard, according to the New York Times.

With opposition from Schumer and Menendez, Republicans need just four more Democrats to pass a measure opposing the deal. Republicans currently have 56 of the 60 votes needed to advance legislation to pass a resolution of disapproval.

Obama, however, has committed to vetoing such a resolution, and Republicans need to secure two-thirds of senators to override the veto.

According to a list compiled by The Hill that details where senators stand on the deal, 21 Democrats have announced their support, while 23 have yet to make a decision.

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