As Republican presidential candidates gird for their eighth debate, this one in Las Vegas, Nev., Tuesday evening, a central question is: how will the Herman Cain phenomenon shape the event?
With the one-time pizza company CEO near or at the top of the GOP field depending on which poll you consult, he's likely to draw more attention from the other candidates at the debate than was true in any of their previous meetings. The two-hour debate will be carried by CNN at 8 pm ET.
Cain's 9-9-9 tax reform plan has been increasingly criticized from the ideological right and left, with critics saying it would raise taxes, especially on low and middle income Americans.
So expect Cain to be put on the defensive by his rivals, especially since his tax plan explains much of his appeal to Tea Party voters. Knock the legs out from under his plan and as it wobbles, Cain's candidacy likely will too, is the obvious strategy for his opponents to follow.
That would fit the pattern of a GOP campaign season so far where whichever candidate surges, with Tea Party support, to the top of the polls finds himself or herself the focus of the other candidates' attacks.
Just how aggressive the criticisms of Cain will be is a related question. Because Cain still appears to be such a long shot for the Republican nomination, lacking the money, organization and establishment blessing that typically lead to the party's top prize, Cain still doesn't appear to be a mortal threat to Mitt Romney's bid.
So Romney, who either leads or slightly trails Cain in the latest polls, could afford to continue his relatively gentle criticisms of Cain's 9-9-9 plan, the tack he took in the previous debate.
In other words Romney, the polished debater, could continue to cruise seemingly effortlessly through Tuesday night's gathering as he has in other encounters. His demonstrated preferred course is that of the frontrunner in the party out of power, leveling his criticisms at the incumbent in the White House, President Obama, and practically ignoring his intraparty rivals.
Romney could then leave the job of making the harsher attacks on Cain to prior Tea Party favorites like Texas Gov. Rick Perry, Rep. Michele Bachmann of Minnesota and Rep. Ron Paul of Texas.
It's in their interests to raise as many doubts as possible about Cain to get some of those anyone-but-Romney voters to return to their fold.
Meanwhile, the more the anti-Romney vote splits, the better it is for the former Massachusetts governor's hopes for the nomination.
Perry, who was once the greatest threat to Romney for the nomination, has seen his poll numbers collapse, in part because of his debate performances, in part because Romney and others have hammered him on illegal immigration and his controversial HPV vaccine mandate.
Perry appears to have pretty much ceded the debate battleground to Romney. But if he hopes to dent Romney's aura of inevitability, scoring some debate points against the man who appears to be a frontrunner with legs would certainly help.
The Texas governor certainly commands a sizable war chest, having raised $17 million in the third quarter compared with Romney's $14 million. What he can't accomplish in the debates, he can try and achieve with the slickly produced videos and TV and radio ads all that money will allow him to buy.
For instance, Perry has a new video with video footage from his energy-plan announcement last week in Pennsylvania, that relies on his campaign's central argument for his candidacy, that in Texas he has overseen robust job creation and can do the same for the nation.
Meanwhile, the Romney campaign has a new video that attacks Perry's Texas jobs claims directly and that seeks to link Perry and Obama as two incumbent politicians who are out of touch with the reality of the current economic situation. (h/t Glenn Johnson of the Boston Globe's Political Intelligence blog for the videos.)
With the debate occurring in Nevada, which continues to have the nation's highest jobless rate (13.4 percent rate in September) it's a perfect venue for all the GOP presidential candidates, especially Romney, to excoriate Obama for allegedly doing too little to fix the economy and perhaps even worsening it.
The twin crises of joblessness and foreclosure in Nevada make the state which Obama won in 2008 one Republicans view as promising for a pickup.
Romney won Nevada in the 2008 GOP caucuses, helped as he was by the state's ample Mormon population and its border with Utah, the state with the largest population of his co-religionists.
And it appears Romney won't have much competition for those voters from his fellow Mormon in the race, Jon Huntsman Jr., the former Utah governor. Putting all his chips on a strong showing in New Hampshire, Huntsman won't be at Tuesday night's debate.
Huntsman has spun his absence as solidarity with New Hampshire's Republican Party and a rebuke to Nevada for moving its presidential preference contest ahead of New Hampshire's, which traditionally comes second after Iowa's caucuses.
New Hampshire has yet to set a new date but is expected to choose one that allows it to keep its second place spot.
But Huntsman is also facing a harsh reality. He has very little money which limits where he can compete, and is barely registering in the polls.
So for Huntsman, it's do well in New Hampshire or bust and virtually no one expects him to do well in New Hampshire.