HEMPSTEAD, N.Y. — True to her predictions, moderator Candy Crowley was an active, aggressive and prominent presence in Tuesday night's second presidential debate.

The longtime CNN reporter and host pressed, poked and prodded President Barack Obama and GOP nominee Mitt Romney when necessary, and occasionally played fact-checker and referee between the two men, during a town-hall debate at Hofstra University in New York.

Despite a format that was supposed to put the spotlight on undecided voters, Crowley's influence was substantial. She wound up asking 10 questions, one fewer than the voters chosen by the Gallup Organization as the primary questioners of the candidates.

Crowley also exerted an unseen influence over the debate. Under the rules, she was part of a team that selected the questions, as well as the order in which they were asked, by a cross section of Americans.

Once the debate began, she also was empowered, at her discretion, to extend the time for discussion of any question. In the end, Obama spoke for more than three minutes longer than the former Massachusetts governor during a debate that ran a bit over its scheduled 90 minutes.

Thanks to the format, the tenor of the debate was more conversational - and occasionally more confrontational - than the first presidential debate two weeks ago. At various times, a candidate rose from his stool and appealed directly to Crowley for time to address a statement by his opponent. At one point, Crowley ordered Romney to sit down.

Crowley's mission was beset by a small and fleeting controversy in the days leading up to the debate. The Obama and Romney campaigns had reservations about her role; they wanted no after-the-fact questions at all - a demand that essentially would have reduced her job to keeping time and holding the microphone for audience members.

But Crowley and the bipartisan Commission on Presidential Debates said they weren't bound by a memorandum of understanding between the campaigns. They stuck to a broader agreement with the campaigns from July that said Crowley's role was to "facilitate discussion," a catchall phrase that Crowley said included the right to pose questions after an audience member weighed in.

The only restriction, which Crowley did observe, was that she couldn't introduce a new topic in her follow-ups or offer her own opinions on the proceedings.

As Crowley told CNN this month: "Once the table is kind of set by the town hall questioner, there is then time for me to say, 'Hey, wait a second, what about X, Y and Z?' "

And that is generally what Crowley did, never wandering too far from the question at hand.

Her attempts to pin down both candidates on specific policies, though, were often rebuffed. When she asked Obama early on whether $4 for a gallon of gas is "the new normal," the president didn't answer, instead attacking Romney about his support of the coal industry.

Similarly, when she followed up a voter's question about immigration by asking Romney about his support for "self-deportation" of undocumented immigrants, Romney ignored her and launched into a critique of the president's inability to pass comprehensive immigration legislation during his first year in office.

She also corrected Romney for saying that Obama had failed to characterize the killing of the American ambassador to Libya last month as an act of terrorism. "He did say that," she said. Her response drew scattered applause from the audience and a retort from Obama: "Can you say that a little louder, Candy?"

Obama and Romney were so aggressive with each other that Crowley at moments struggled to separate them verbally. In that sense, she was similar to ABC's Martha Raddatz, who kept last week's vice-presidential debate largely within the rules.

Crowley seems unlikely to take the public drubbing that befell PBS' Jim Lehrer, who was widely criticized for his open-ended questions and for permitting Obama and Romney to exceed time limits in their first presidential debate.

For the record, Crowley was the fourth woman to moderate a presidential debate. The first was National Public Radio's Pauline Frederick, who moderated the second debate between President Gerald R. Ford and Jimmy Carter in 1976. Barbara Walters of ABC News moderated the third Carter-Ford debate that year, as well as the 1984 debate between President Ronald Reagan and challenger Walter Mondale.

Carole Simpson, then of ABC News, was the moderator for a town-hall debate involving President George H.W. Bush, Bill Clinton and Ross Perot in 1992.