A liberal Jewish congressman tore into the liberal Jewish lobbying firm J Street this week, saying the organization’s “brains have fallen out” after it urged the Obama administration not to veto a proposed U.N. resolution condemning Israel.

Rep. Gary Ackerman, D-N.Y., effectively cut ties with J Street, a group that raised campaign money for him last year, in a searing press release Tuesday. The tipping point was the group’s call for the administration to clear the way for a Palestinian-backed proposal at the U.N. Security Council condemning Israel’s settlement expansion.

“I’ve come to the conclusion that J-Street is not an organization with which I wish to be associated,” Ackerman said.

J Street bills itself as the voice for “pro-Israel, pro-peace Americans,” and is often critical of Israel’s policies in the process. That hasn’t stopped Ackerman from associating with the group before, but the organization’s stance on the resolution triggered a harsh response.

“The decision to endorse the Palestinian and Arab effort to condemn Israel in the U.N. Security Council is not the choice of a concerned friend trying to help. It is rather the befuddled choice of an organization so open-minded about what constitutes support for Israel that its brains have fallen out,” he said. “America really does need a smart, credible, politically active organization that is as aggressively pro-peace as it is pro-Israel. Unfortunately, J-Street ain’t it.”