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

Dan Janison has been a reporter at Newsday since 1997.

Forget the expectation games played by the campaigns when they say the pressure to perform rests with the other side.

The truth is, both candidates in the first general-election debate on Monday have much to lose by messing up.

Whether and how they mess up will, of course, be spun and debated after the debate in Nassau County.

Perhaps Hillary Clinton loses mojo if she sounds too evasive.

Perhaps Donald Trump loses points if he looks too ignorant.

Or vice versa.

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It figures to matter, because not all voters will have made up their minds going into this first of three face-to-face events.

Two weeks ago, ABC News reported that 23 percent of those interviewed for a poll said they expect the debates to affect which of the two candidates they may choose.

There are traps either candidate can fall into, risks they have been told to avoid, unintentional impressions that can be made.

One is a display of temper. If either of them rages at the other in a personal way that looks out of control, it would feed suspicion that this person shouldn’t be the nation’s top elected executive.

Another trap is a robotic repetition of a sound bite. Last February in New Hampshire, Marco Rubio used the same line four times regarding President Barack Obama in a multiway GOP primary debate.

It cost him. The Florida senator even apologized later. “It’s on me,” he said. “I did not do well on Saturday night, so listen to this. That will never happen again.”

Visual antics also can be counterproductive for a candidate.

Republican Rick Lazio famously created his own trap 16 years ago when he looked as if he was trying to intimidate Clinton during a U.S. Senate debate by invading her personal space and demanding she sign a certain pledge.

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By his own admission later, that was a televised error.

Last time out, Obama was widely panned for a low-energy performance in the first debate against challenger Mitt Romney, held on Oct. 4, 2012, at the University of Denver.

By the time he reached Hofstra University for the second debate two weeks later, Obama sounded more aggressive. He talked over his opponent, chided him at times, and went into longer monologues.

So a candidate can recover from initial mistakes, depending what they are.

Contrary to post-debate broadcast jargon, the concept of a “knockout blow” is usually irrelevant in these displays.