Two polls released Thursday show different pictures of the Republican race. In one, Herman Cain and Mitt Romney are tied, and in the other, Cain maintains the edge he has held for the past two weeks.

An Oct. 12 Rasmussen Reports poll of 1,000 likely Republican primary voters found Cain and Romney tied at 29 percent each, with a margin of error of plus or minus 3 percentage points.

Their closest competitor, Newt Gingrich, had 10 percent. Former frontrunner Rick Perry had 9 percent, and the other candidates were all in the low single digits: 5 percent for Ron Paul, 4 percent for Michele Bachmann and 2 percent each for Rick Santorum and Jon Huntsman.

An Oct. 6-10 NBC News-Wall Street Journal poll of 336 likely Republican primary voters found different results. Cain had 27 percent support and Romney 23 percent support, with a margin of error of plus or minus 5.35 percentage points.

No Others Garner 20 Percent

Behind them, Perry had 16 percent, Paul 11 percent, Gingrich 8 percent, Bachmann 5 percent and Huntsman 3 percent.

Statistically, the Rasmussen poll was stronger than the NBC News-Wall Street Journal poll in terms of sample size and margin of error. The NBC News-Wall Street Journal poll included 1,000 voters overall, but only 336 of them -- the self-identified likely Republican primary voters -- were asked about their preferred Republican candidate.

Nonetheless, the discrepancy between the two polls underscores the volatility of the Republican race and the difficulty of predicting the nominee at this stage in the game.

Obama Ahead in Both Hypothetical Match-Ups

Both polls found President Obama leading both Cain and Romney in hypothetical matchups, but the margins differed. In the Rasmussen survey, Obama led Romney 43-41 percent and Cain 42-39 percent. In the NBC News-Wall Street Journal survey, he led Romney by the same margin, 46-44 percent, but he led Cain much more decisively, 49-38 percent.

In more good news for Obama, he led a generic Republican 44-42 percent: a slim margin, but a marked improvement from August, when he trailed a generic Republican 44-40 percent.