Vice President Joe Biden served up the worst gaffe of any of the 2012 debates, in a moment that will harm not only him but also his boss. Sure, the obnoxious grimacing and the mannerisms will be mocked relentlessly, but it was his egregious misstatement on Benghazi that will now plague the Obama-Biden ticket.

The exchange went like this:

MARTHA RADDATZ: And they wanted more security there.

BIDEN: But we weren’t told they wanted more security there. We did not know they wanted more security there.

That was just flat-out false. As many fact-checkers, reporters and pundits instantly pointed out, multiple State Department employees testified just the day before that their pleas for more security were denied. Josh Rogin recollected:

In fact, two security officials who worked for the State Department in Libya at the time testified Thursday that they repeatedly requested more security and two State Department officials admitted they had denied those requests.

“All of us at post were in sync that we wanted these resources,” the top regional security officer in Libya over the summer, Eric Nordstrom, testified. “In those conversations, I was specifically told [by Deputy Assistant Secretary of State Charlene Lamb] ‘You cannot request an SST extension.’ I determined I was told that because there would be too much political cost. We went ahead and requested it anyway.”

Nordstrom was so critical of the State Department’s reluctance to respond to his calls for more security that he said, “For me, the Taliban is on the inside of the building.”

“We felt great frustration that those requests were ignored or just never met,” testified Lt. Col. Andrew Wood, a Utah National Guardsman who was leading a security team in Libya until August.

Was Biden lying? Was he really so clueless that even now he didn’t know what had occurred? In either case, it will cement the notion that the administration wasn’t paying attention to events in Libya (even now!).

Rep. Paul Ryan’s adviser, Dan Senor, issued a blistering statement late last night: “Vice President Biden tonight continued the Administration’s pattern of misleading the American people about events in Libya. He wrongly stated that the Administration was not aware of requests for more security from our diplomatic facilities in Libya. But we now know from the sworn testimony of two U.S. security officials who were stationed in Libya that there were repeated requests for more security in the face of rising threats. We need leaders who will be truthful with the American people and who are informed about vital issues of national security. Joe Biden’s comments point to the larger failures of the Administration to be completely transparent about the terrorist attacks in Benghazi and the security situations leading up to the attacks.”

That’s about the size of it. The Post’s Glenn Kessler reamed Biden: “Biden’s bold statement was directly contradicted by State Department officials just this week, in testimony before a congressional panel and in unclassified cables released by a congressional committee.” NBC’s Andrea Mitchell likewise called out Biden:

Biden’s flub illustrates why Obama deputy campaign manager Stephanie Cutter on Thursday said Benghazi was only about politics; apparently for the Obama-Biden team that’s about the size of it, thereby alleviating them of the need to figure out what happened and to speak truthfully to the American people.

Foreign policy has now become a liability for the Obama campaign. This will make it even more so.