Vice President Joe Biden on Thursday ripped Republicans who opposed reauthorizing the Violence Against Women Act, mocking them as a “Neanderthal crowd.”

“I'm going to say something outrageous," Biden told attendees at a dinner reception hosted at his residence celebrating the 19th anniversary of the legislation. "I think I understand the Senate better than any man or woman who's ever served in there, and I think I understand the House ... I was surprised this last time ... The idea we still had to fight? We had to fight to reauthorize?"

"Constitutional violation?” Biden added sarcastically, dismissing GOP opposition. “Yeah, come on!"

Biden, who crusaded against domestic violence during his lengthy career in the Senate, said the legislation had saved countless lives.

The law stiffened penalties for domestic violence and increased federal support for organizations that help victims.

Some Republicans balked at Democratic attempts to offer additional protections for Native Americans, lesbians and transgendered women.

Ultimately, 87 Republicans in the House joined their Democratic colleagues to pass the Senate version of the bill earlier this year.

Biden, in one of his signature off-the-cuff exchanges, also highlighted his high-profile support for same-sex marriage last year. The vice president famously offered his endorsement of gay matrimony before President Obama, getting ahead of the administration and forcing Obama to back same-sex nuptials earlier than planned.

"I make no apologies on the issue of marriage," Biden proclaimed to the small gathering of supporters.