WASHINGTON (TIP): New York Sen. Chuck Schumer dealt a blow to President Barack Obama‘s nuclear deal with Iran, announcing during the Republican presidential debate Thursday night that he planned to vote against the agreement now under review in Congress.

Schumer’s opposition hurts the president’s efforts to woo the support of Senate Democrats, who he needs to be his bulwark against a likely Republican attempt to override a veto. But although Schumer said in a 1,600-word statement that he would side against the deal, he did not say whether he would vote to override a veto.

“I believe Iran will not change, and under this agreement, it will be able to achieve its dual goals of eliminating sanctions while ultimately retaining its nuclear and non-nuclear power,” Schumer said.

The Iran nuclear deal was also a big target during the Republican presidential debate. Scott Walker said he’d cancel it on Day One. Mike Huckabee said it left “hostages” behind. And Donald Trump said it was “a disgrace” for a president “who doesn’t have a clue.”