In keeping with that background — not to mention her aggressive moderation style — Raddatz opened the vice presidential debate by going after Vice President Biden on the Sept. 11 attacks on U.S. interests in Benghazi, Libya, a tragic episode that claimed the lives of four Americans. Raddatz:

RADDATZ: It was a pre-planned assault by heavily armed men. Wasn’t this a massive intelligence failure, Vice President Biden?

By no means a softball. That said, the real scandal of Benghazi was not quite so much that the administration failed to forecast it but rather that its explanations for the attack hewed toward excuses about spontaneous protests and an anti-Muslim video.

When his turn came around, Ryan gave the administration’s post-attack shiftiness its due:

When you take a look at what has happened just in the last few weeks, they sent the U.N. ambassador out to say that this was because of a protest and a YouTube video. It took the president two weeks to acknowledge that this was a terrorist attack.

He went to the U.N. and in his speech at the U.N. he said six times — he talked about the YouTube video.

Then Raddatz followed the moderator’s ideal, attempting to sprinkle the pain evenly: She asked Ryan whether ticket-topper Mitt Romney might have jumped the gun with his early statement lambasting the Obama administration. “Was that really appropriate right in the middle of the crisis?” Ryan responded well.

Next it was back to Benghazi with Biden. Raddatz unfurled this laundry list of inquiries:

RADDATZ: What were you first told about the attack? Why — why were people talking about protests? When people in the consulate first saw armed men attacking with guns, there were no protesters. Why did that go on (inaudible)?

Those questions prompted this Biden response:

Because that was exactly what we were told by the intelligence community. The intelligence community told us that. As they learned more facts about exactly what happened, they changed their assessment. That’s why there’s also an investigation headed by Tom Pickering, a leading diplomat from the Reagan years, who is doing an investigation as to whether or not there are any lapses, what the lapses were, so that they will never happen again.

RADDATZ: And they wanted more security there.

BIDEN: Well, we weren’t told they wanted more security there. We did not know they wanted more security again. And by the way, at the time we were told exactly — we said exactly what the intelligence community told us that they knew. That was the assessment. And as the intelligence community changed their view, we made it clear they changed their view.

That’s why I said we will get to the bottom of this. You know, usually when there’s a crisis, we pull together. We pull together as a nation. But as I said, even before we knew what happened to the ambassador, the governor was holding a press conference — was holding a press conference. That’s not presidential leadership.

Repetition is in order here: “We did not know they wanted more security again.” Oh yeah? That contention was freshly at odds with the previous day’s news, when a House committee grilled administration officials on the attacks. As the Washington Post’s Glenn Kessler pointed out in his post-debate fact-check:

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.

“All of us at post were in sync that we wanted these resources,” said Eric Nordstrom, the top regional security officer in Libya earlier this year. A Utah national guardsman who led a security team, Lt. Col. Andrew Wood, said: “We felt great frustration that those requests were ignored or just never met.”

An Associated Press account of the Wednesday congressional hearing on this topic features this sentence: “A top State official acknowledged she had declined to approve more U.S. security as violence in Benghazi spiked, saying the department wanted to train Libyans to protect the consulate.”

A great debate has arisen over the role of the moderator in these clashes. Can that person do on-site fact-checking? That’s a difficult imperative. Yet if ever there was a moment to give the gotcha model a spin around the block, here it was: A moderator steeped in foreign policy and security issues; a top official essentially contradicting testimony from a congressional session held the day before; a perfect furniture arrangement; and time. It didn’t happen — the debate moved on to other topics.

Instead of nailing Biden on the spot for this dicey argument, Raddatz leaves his words in the hands of fact-checkers and cable news. We’ll see how that goes.