The moment is here.

The top candidates for the Republican nomination for president took the stage Thursday night in Cleveland, Ohio, for the second of two debates sponsored by Fox News -- and while it's certain they'll come out swinging, the question is: at who?

While the seven other Republican hopefuls spent much of the first debate doing their best to hammer home the message that Hillary Clinton represents four more years of President Obama -- they also didn't have billionaire Donald Trump on stage to contend with.

In the earlier debate, the candidates largely avoided the “elephant not in the room,” and instead trained their fire on the Obama years -- with promises to roll back ObamaCare and take aim at the Iran nuclear deal.

Chris Stirewalt, author of the daily column “Fox News First,” has suggested that while attacks  on the Democrats will prevail, the second debate could see plenty of static between the candidates, too, especially if they are trying to establish their dominance among the pack.

“There are plenty of feuds and rivalries among these candidates and much of the debate may be driven by how much and how often they erupt. Remember that these folks are all fierce competitors with plenty of ego,” he said.

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Aside from Trump, the prime time event will include: former Florida Gov. Jeb Bush; Wisconsin Gov. Scott Walker; former Arkansas Gov. Mike Huckabee; surgeon Ben Carson; Texas Sen. Ted Cruz; Florida Sen. Marco Rubio; Kentucky Sen. Rand Paul; New Jersey Gov. Chris Christie; and Ohio Gov. John Kasich.