Moderators Anderson Cooper and Martha Raddatz addressed the audeince before the second presidential debate between Donald Trump and Hillary Clinton. (Jim Young/Reuters)

Martha Raddatz moderated the vice-presidential debate four years ago, and this year she got the call to preside over Sunday's presidential debate, along with Anderson Cooper. Raddatz also moderated a Democratic primary debate in December.

Based partly on that record, we have some idea of what to expect at Washington University in St. Louis on Sunday. Here are five things to know about Raddatz that might offer a preview of the second round between Hillary Clinton and Donald Trump.

Raddatz's first question at the 2012 vice-presidential debate was about Benghazi

Republicans, rejoice!

This was the opening question to Vice President Biden four years ago: "I would like to begin with Libya. On a rather somber note, one month ago tonight, on the anniversary of 9/11, Ambassador Chris Stevens and three other brave Americans were killed in a terrorist attack in Benghazi. The State Department has now made clear there were no protesters there. It was a pre-planned assault by heavily armed men. Wasn't this a massive intelligence failure, Vice President Biden?"

The key phrases there were "no protesters" and "pre-planned assault." In the current election, Republicans have hammered Clinton, the secretary of state at the time, for her department's initial claim that the attack was preceded by spontaneous protests against a video mocking the prophet Muhammad, which had provoked demonstrations in Cairo the same day.

A similar question to Clinton on Sunday would make sense, given the Democratic nominee's emphasis on foreign policy experience as one of her top qualifications and Raddatz's role as ABC's chief global affairs correspondent.

Raddatz is not afraid to follow up

Don't expect Raddatz to simply ask questions and sit back while the candidates do as they please with their allotted times. During the vice-presidential debate in 2012, she often jumped in to keep the candidates on topic or demand specifics.

This exchange with Biden is a good example:

BIDEN: These guys bet against America all the time.

RADDATZ: Can we talk — let me go back to Libya.

BIDEN: Yeah, sure.

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 —

BIDEN: 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.

Raddatz hinted at a question about nuclear weapons

After the first Clinton-Trump debate, Raddatz remarked on "Good Morning America" that she was confused by Trump's response to a question about implementing a "no first use" nuclear policy for the United States, which President Obama is considering.

"I would certainly not do first strike," Trump said. "I think that once the nuclear alternative happens, it's over. At the same time, we have to be prepared. I can't take anything off the table."

"We had no idea what he was talking about in the end," Raddatz said, "whether he wanted first use or whether he didn't want any first use. Maybe that next debate. We'll see."

If Raddatz wants some clarity, she will be in a position to ask.

Raddatz has grilled Trump about his temperament

After Trump declared last year that Sen. John McCain (R-Ariz.) is "not a war hero," Raddatz conducted a very tough interview with the real estate mogul.

"There seems to be a pattern, Mr. Trump," Raddatz said. "When you’re criticized or attacked, you often respond with name-calling, using terms like ‘dummy,’ ‘loser,’ ‘total losers’ on Twitter and elsewhere. You even demean some people’s physical appearance. Is that something you would continue doing if you were president? Isn't that language beneath the office of the president?"

Since then, Trump hasn't exactly put questions about his temperament to rest. He spent the days after the first debate feuding with former Miss Universe Alicia Machado, saying on Fox News that "she gained a massive amount of weight, and it was a real problem."

Another question about Trump's rhetoric could be in order.

President Obama attended Raddatz's wedding to her second husband

This is a fun fact that the folks at Breitbart love, so expect to hear all about it if Team Trump decides to paint Raddatz as biased after Sunday's debate.

Here's the deal: Raddatz's second husband, Julius Genachowski, was Obama's classmate at Harvard Law School. Obama attended the Raddatz-Genachowski wedding in 1991, long before entering national politics. As president, he appointed Genachowski as chairman of the Federal Communications Commission, but Raddatz and Genachowski had been divorced for more than a decade by then.

It's a stretch to say Raddatz is too close to Obama — and, therefore, partial to Clinton — based on the president's friendship with a man to whom she has not been married for 19 years. But conservative news sites used the connection to suggest that Raddatz was biased when she moderated the vice-presidential debate in 2012. Don't be surprised if the complaint resurfaces.

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