Dan Janison Melville. N.Y. Tuesday January 26, 2010. Daniel Janison,

Dan Janison has been a reporter at Newsday since 1997.

The second presidential debate Sunday in St. Louis promises a taste of the unpredictable for both candidates, because half the questions will come from an audience of uncommitted voters, picked by the nonpartisan Gallup Organization.

By now it is clear that Donald Trump basks in the sound of rally-goers egging him on as he wanders off topic, sometimes into controversial or less-than-linear monologues.

Hillary Clinton prefers a different venue where she can deliver responses that are prepared and planned in advance.

She drew fire after one forum in May when, in talking up her renewable-energy proposals, she said: “We’re going to put a lot of coal miners and coal companies out of business.”

Both candidates risk spontaneous error — and both have a shot at the prized moment where they visibly win someone over with a convincing reply.

In contrast to the sight of two candidates behind lecterns, these two will be subject of examination of their body language, gestures and poses. They may roam or sit.

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After their first debate at Hofstra University last week, the Trump camp complained about a faulty microphone and charged bias by a moderator. Trump, clearly on the defensive, said, “I may hit her harder” in the second faceoff.

He called her nasty, but said, “I can be nastier than she ever can be.” Perhaps to manage expectations, Clinton campaign manager Robby Mook predicted Trump will be better prepared than last time and not salacious.

But it remains to be seen how any plan for the Republican to go off on the infidelities of Bill Clinton, as some suggest, would be worked into the dialogue.

Would it be jammed in abruptly, in reply to a question about manufacturing jobs? Could it be done smoothly, in reaction to someone asking about the political place of personal morality?

Last month Clinton and Trump took part in a military forum aboard the U.S. Intrepid museum in Manhattan, where they separately faced questions from veterans.

Clinton was viewed as lawyerly, defensive and off-base on details. Trump drew flak for statements on Russia’s Vladimir Putin, female combat troops and the firing of generals and admirals.

Bloomberg News notes that past town hall debates have produced such questions as: How do your tax plans, if approved, affect me? What do you say to my friends who say you sound too vacillating? How will you learn things you don’t know?

Voters whose minds are made up may view Trump-Clinton II nervously, on behalf of their candidate. Direct dialogues with living, breathing voters are especially risky in a year when both contenders are so negatively rated in polls.