Zogby has been declining in respect among pollsters over the past several years, so it’s hard to give this too much credence.

But Herman Cain ahead of the GOP field with 20 points to spare? Clearly something’s going on.

In news sure to inject shock and awe into the Republican political primary season, a Zogby poll released Thursday showed Herman Cain leading the Republican field, topping former front-runner Mitt Romney by an astonishing 20 points. Cain would also narrowly edge out Obama in a general election, the poll found, by a 46-44 margin.

Romney, the former Massachusetts governor, would lose by a point to the president, 40 percent to 41 percent. Texas governor Rick Perry, who has slipped in the polls of late, would lose to the president 45 percent to 40 percent.

The poll found that 38 percent of Republican primary voters said they would vote for Cain if the primary were held today. Eighteen percent said they would throw their support to Romney, while 12 percent each said they would vote for Perry and Texas congressman Ron Paul. No other candidate attracted double-digit support.

Perry has $15 million in the bank and he’s already taken as much abuse as he can possibly take, so he can’t be counted out of this race.

But clearly Cain has momentum here.

Twenty-points-ahead-of-everybody-else momentum? That’s probably pushing it.

What’s perhaps most interesting is that Obama can’t get better than 45 percent against any of the three first-tier GOP candidates. If that’s all he’s getting in these polls and Zogby is even remotely correct, then Obama can’t beat any of them. Take Perry, for example – if Zogby is showing a 45-40 Obama spread with 15 percent undecided, the question is whether Perry can do better than two-thirds of those people on Election Day.

Lots of old political hands will tell you undecideds usually break 4-to-1 for the challenger against the incumbent. That would mean Perry beats Obama 12-3 on those undecideds and wins the popular vote 52-48. By that standard Cain wins 54-46 and Romney wins 55-45 or so.

Romney probably does best, if the 4-to-1 thing holds up and Zogby’s numbers are to be believed, but not by a huge amount. This “electability” business he’s been selling is overrated; it’s premised on the same thinking that led the GOP electorate down the John McCain path in 2008, and that didn’t work out so well.

Everybody is saying that Perry’s campaign is the one in trouble. His camp would rather not see Cain take off, for sure, but that a political newcomer without any money to speak of could leapfrog Romney so quickly after catching a spark has to be a real threat to the Massachusetts governor.

This “It’s ultimately going to be Romney” narrative being fed by the Beltway crowd seems to ignore a pretty obvious fact; namely, that a large majority of the GOP electorate doesn’t want to nominate him.

Either Cain sustains his current boomlet and finds some money to put behind it, or he subsides and Perry regains the support he bled to Cain as he gets a little more polish and puts some of that war chest to use. But there are no polls showing Romney above 25 percent, and that simply isn’t enough to get him the nomination.