It’s debate night in Vegas and some very loaded dice are headed Herman Cain’s way. The former Godfather’s Pizza executive will draw a significant amount of attention as his Republican presidential rivals attempt to pin him down on the specifics of his 9-9-9 tax plan, which has helped his campaign significantly, and why he was against a national sales tax before he was for it.

“Now that we’re digging into the details of the plan, it’s important for Cain to explain why it’s necessary, and to allay many conservatives’ concerns about the imposition of a new national sales tax that they are deeply concerned about,” said Brian Darling, a senior fellow at the conservative Heritage Foundation. “They worry that once you establish a national sales tax and a new revenue stream for the federal government, it’s going to be heard to 'reel that in' to make sure it doesn’t become just another means for the government to grow.”

Cain also will need to appear a lot more knowledgeable about foreign policy if he wants to stay at the top. Answers like: “When they ask me, ‘Who is the president of Ubeki-beki-beki-beki-stan-stan?’ I’m going to say, ‘You know, I don’t know’,” will no longer do.

Mitt Romney, who has consistently held his position in the top tier, also will be a target. He of all of the candidates has run the most disciplined campaign and, according to many pundits, is just biding his time until the general election. As GOP strategist Mike Murphy, who likes to drink and tweet the debates, observed last week, “Mitt looks like he is watching these guys and all he can do is hum 'Hail to the Chief' in his head.”

Minnesota Rep. Michele Bachmann, Newt Gingrich and others who find themselves trailing the former Massachusetts governor, will want to break out from the bottom of the pack and try to take him down a notch or two, Darling predicts, by going after various positions he’s taken on the same issues, like abortion and universal health care.

“Debates are not my strong suit,” Texas Gov. Rick Perry told reporters after a visit with his frat brothers at Dartmouth, the site of last week’s forum.

He’s not kidding. Following some “dramatic stumbles,” as Darling put it, conservatives are losing confidence in him. He has reportedly been participating in debate prep, although its effectiveness was not immediately apparent last week. The question tonight will be: Has Perry finally gotten his mojo back?

Win, lose or fold, Darling says, the debates are great forums that enable the candidates to not only promote their positions, but to also keep going the “drumbeat” of opposition to President Obama’s “failed policies.”

“The Republicans, independents and Democrats who are watching the debates are hearing that message over and over again,” he said.

(Photo: Steve Pope/Getty Images)