Herman Cain has surged into the lead in several national polls of GOP primary voters, but he remains in second place in most polls of early voting states.

That difference points to the challenge faced by Cain, who lacks the ground troops important in the Iowa caucuses and New Hampshire primary, if he wants to turn his momentum into victories in early 2012.

In the Iowa caucuses, Real Clear Politics's average of recent polls show Romney leading Cain 22 percent to 18 percent. Cain is further behind Romney in New Hampshire, where the former Massachusetts governor is a heavy favorite.


Iowa likely represents Cain's best chance for a surprise victory. Caucuses are notoriously difficult to predict by polling and often favorable to new candidates with energized bases, and Cain is within striking distance. Rep. Michele BachmannMichele Marie BachmannEvangelicals shouldn't be defending Trump in tiff over editorial Mellman: The 'lane theory' is the wrong lane to be in White House backs Stephen Miller amid white nationalist allegations MORE (R-Minn.) the early favorite in Iowa and winner of the Ames Straw poll, has faded in recent weeks.

One poll from Public Policy Polling - a Democratic firm - even shows Cain leading, by a 30 percent to 22 percent margin.

Cain supporters are encouraged by this news, believing that Romney has hit a “glass ceiling” where no more than a quarter of Republicans are willing to vote for him, especially in caucus states where support requires greater effort.

From the campaign's perspective, an energized Cain could continue to draw money and votes from other candidates and undecided voters, amassing a coalition that will push him past Romney.

But Iowa in particular demonstrates how difficult that may be. Even as her national poll numbers have cratered, Bachmann maintains an average of 12 percent support in Iowa.

Meanwhile, Rick Perry is unlike to fall far below the 10 percent he has averaged in recent months. It would be hard to imagine things going worse for a campaign than they have for Perry since his rollout. The Texas Governor will be able to flex his financial advantage to build a better ground game.

Cain will have to scrap with those two - along with Romney and Ron Paul, who always posts a good showing in caucus contests - for the 21 percent who remain undecided.

If Cain is unable to win or place a close second in Iowa, the following weeks could be tough for the candidate.

In New Hampshire, Romney enjoys the largest lead of any candidate in any state polled so far. An averaging of recent polls shows Romney leading Cain by a margin of 40 percent to 15 percent, and the most favorable poll for Cain - a Harvard/Saint Anselm survey released last week - still shows the Godfather's Pizza CEO trailing by 18 percentage points.

From New Hampshire, the GOP contest will head west to Nevada, where Romney can rely on a strong Mormon turnout to buoy his prospects. Romney won the contest with more than 51 percent of the vote in 2008, and pollsters haven't even surveyed the state since early September.

So Cain might be heading into South Carolina - the first state where he now leads in the polls - on the heels of three straight defeats.

The Palmetto State might not offer much of a firewall, either – Cain currently only leads Romney by a single percentage point, 26 percent to 25 percent, according to the latest numbers from the American Research Group.

Like Iowa, South Carolina provides unique challenges from other candidates - Newt Gingrich, expected to be less of a factor in early contests, has steadily hovered between 8 and 10 percent in the polls there, while Rick Perry continues to maintain numbers that beat his national averages.

Still, there is a plausible path to victory for Cain, especially as the early GOP calendar continues to shuffle. Some candidates - including Cain - are currently threatening to boycott the Nevada caucus for squeezing New Hampshire's traditional week-before-and-after window, and the Granite State may move its primary into early December. If both happen, Romney's early momentum could be muted, especially if Cain places well or wins in Iowa.

The national polls also offer comforting signs for Cain: Romney has never cracked an average above 25 percent in the polls, and around 18 percent of voters are still up for grabs. If the Cain campaign's thinking holds - those voters would have already jumped to Romney if they were enthusiastic about him, and the Massachusetts governor's stagnant poll numbers betray a lack of enthusiasm - Cain could quite plausibly ride upset wins to the eventual Republican nomination.