Gallup poll: Unsteady December for GOP field

Gallup's daily tracking poll shows a tightening GOP presidential field, with Newt Gingrich losing steam nationwide and Mitt Romney regaining some momentum within the last week.

Gingrich now has the backing of 29% of Republican voters, down eight percentage points from his peak of 37% in early December, according to the rolling poll, which measures five consecutive days of polling data.

For the ongoing poll, Gallup surveys more than 1,000 Republican registered voters on a daily basis, and the poll drops the oldest of five days each day and adds results from the most recent day of polling.

The former House speaker, who sped to the top of the polls in November, has seen his numbers steadily drop over the last two weeks, a time period in which Gingrich has undergone swarming attacks from his opponents--both in ads and in the debates.

Meanwhile, his closest competitor, Mitt Romney, has made modest gains in the last week, up to 24% from 22%, where he's held steady since the beginning of November.

Romney's campaign has been marked by a noticeable change in strategy, as he now frequently takes part in media interviews and doesn't shy from criticizing Gingrich.

The former speaker, on the other hand, has repeatedly called for a positive campaign and vowed to avoid going negative, although he slipped at the debate on Saturday and directly attacked Romney on stage.

Gingrich also made headlines on Monday when he called on Romney to return the money he earned during his tenure at Bain Capital, saying Romney was responsible for "bankrupting companies and laying off employees."

The remark came in response to Romney's urging that Gingrich return the more than $1.6 million he earned from Freddie Mac as a consultant.

Rising numbers for Texas Rep. Ron Paul also denote signs of a GOP horserace shake-up. According to the tracker, the congressman is in third place with 10%, up from 8% last week.

Those figures mirror similar patterns in polls measuring support in states with the first nominating contests. In Iowa, especially, Paul seems to be locked in a battle with Romney for second place, with Gingrich in the lead.

The results come less than three weeks before the Iowa Caucuses, positioning the top three candidates in an expected showdown for first place.

Coming in fourth place, Minnesota Rep. Michele Bachmann took in 7%, up from 5% last week. She essentially replaced Perry, who was in fourth place last week but has since dropped to fifth with 5% of support.

Former Pennsylvania Sen. Rick Santorum also saw a slight boost from 2% last week up to 4%, as of Wednesday. Meanwhile, former Utah Gov. Jon Huntsman came in with 2%.

The latest results--as of Wednesday--are based on five days of interviews conducted Dec.10-14, with a sampling error of plus or minus four percentage points.