In an American Research Group poll taken February 15-16, Clinton leads Obama 49 to 43 percent.

CNN: 150 delegates up for grabs Tuesday

Indeed, an American Research Group poll released on Christmas Eve showed Huckabee losing his lead and Clinton widening hers.

CNN: Campaigns look to seal the deal in Iowa

An American Research Group poll conducted March 5-6 of likely primary voters had Obama leading Clinton 58 percent to 34 percent with 5 percent supporting another candidate and 3 percent unsure.

CNN: Obama rejects being Clinton's No. 2