Sen. Richard Blumenthal LAW ’73 has become the last member of Connecticut’s Washington delegation to announce his support for President Barack Obama’s nuclear deal with Iran.

Blumenthal and three other senators — Maria Cantwell from Washington, Gary Peters from Michigan and Ron Wyden from Oregon — made public statements in support of the deal yesterday, bringing the number of Democratic in the Senate advocates to 42. Last week, the President garnered the support necessary in the Senate to prevent lawmakers from overriding a veto on any Congressional resolution against the deal, and the support announced Tuesday would effectively prevent Obama from needing to exercise such a veto. Blumenthal’s announcement arrived after several weeks of deliberations, as the Connecticut senator fielded aggressive lobbying from groups both for and against the deal.

“While this is not the agreement I would have accepted at the negotiating table, it is better than no deal at all,” Blumenthal said in a briefing Tuesday. “And it can be made even better through unilateral American action and collaboration with our European allies.”

In assessing the merits of the nuclear agreement, Blumenthal said he wanted to ensure that the deal prevents Iran from obtaining nuclear arms, and that it does so peacefully. As a result, he concluded that rejecting the deal presented an “unacceptable” risk, as the U.S.’s formal negotiation partners and allies have indicated no intention of making further negotiations.

Blumenthal indicated that while he supports the deal, he also plans to propose legislation with Maryland Sen. Ben Cardin, one of four senators who have openly opposed the deal. This proposed legislation would address potential issues in the deal that may be revealed during congressional review, Blumenthal said. These bills would allow for “snap-back” policies — or re-instituting sanctions, should Iran fail to comply with the deal — and they would improve upon security assistance to Israel and ensure oversight of the deal as whole.

Proponents and opponents of the deal worked for weeks to encourage the senator to vote one way or the other.

Special interest groups, including the American Security Initiative and Citizens for a Nuclear-Free Iran, have run television ads in the state against the deal. At the same time, MoveOn, a liberal activist organization, has launched grassroots efforts in the past few weeks in an attempt to sway the senator, from meeting in front of Blumenthal’s Hartford office to bringing a mobile billboard — named the SchumerMobile, as it targets New York Sen. Chuck Schumer for opposing the deal — to Stamford.

MoveOn’s electoral field director Matt Blizek said that Blumenthal had been engaging and open to concerns from both sides of the agreement.

Gary Rose, chairman of the Department of Government and Politics at Sacred Heart University, said he thinks that, in spite of concerns from his Jewish constituents, Blumenthal might have decided to vote in favor of the deal to align with the majority of his party, as opposed to satisfy a specific special interest group.

University of Connecticut professor of Political Science Ron Schurin offered a different perspective, saying that Blumenthal, knowing that his vote would no longer make a substantial difference, may have then simply chose to declare his support to align with the state majority opinion.

While lobbyist groups, including MoveOn, praised Blumenthal for his decision, August Wolf, the Republican challenger for Blumenthal’s Senate seat, said in a statement that Blumenthal lacked integrity on the issue by waiting until the last possible moment before counting the votes and siding with Obama.

The Senate was in session for the first time Tuesday after August Recess and is expected to vote on the deal by next Thursday.