Sen. Brian Schatz (D-Hawaii) is supporting the Iran nuclear deal, becoming the 17th Democratic senator to do so publicly and getting President Obama halfway to the 34 senators needed to implement the agreement.

“Iran must never be allowed to have a nuclear weapon, and that is why I support this agreement. This is the best possible way to deny Iran from acquiring the bomb. It is what is best for the United States, Israel, and peace in the region,” Schatz said in a statement on Monday.

{mosads}Republicans are planning a vote to reject the nuclear deal in September. If they succeed, the president has promised to veto that resolution. Critics of the agreement would need two-thirds each chamber of Congress to override the veto.

Obama needs the support of at least 34 senators to sustain his veto. According to The Hill’s Whip List, so far 17 Democrats favor the deal and another seven are leaning yes.

Sen. Charles Schumer (N.Y.) became the first Senate Democrat  announce his opposition to the deal last week, and another 21 are publicly undecided, according to The Hill’s count.

Schatz appeared to be leaning yes before he announced his support.

“After multiple readings, numerous briefings with officials, discussions with experts outside of government, consultations with my constituents and my colleagues, I am satisfied that the Joint Comprehensive Plan of Action is the best approach to deny Iran a nuclear weapon and place its nuclear program under strict international supervision,” he said in his statement.

Schatz argued it was the best available option. He said that if Congress kills the deal and continues U.S. sanctions on Iran, other nations would not follow along and the restrictions that convinced Iran to negotiate “will certainly crumble.”

“While there are legitimate concerns about the agreement, we must remember this plain fact: there is no other alternative that achieves these results. We do not have the luxury of being able to pick this deal apart,” he said.

Military action would also not achieve the same results, he said.

“This agreement should not be compared to an imaginary deal where Iran rolled over, and eliminated all its centrifuges and all peaceful nuclear energy generation. That was never seriously on the table,” he said.

“It should be compared to its real world alternative — an unraveling of the international sanctions, Iran moving ever faster towards the bomb, and our country left with few choices other than another war in the Middle East.”