In addition, one-quarter of the party has an unfavorable view of Gingrich. That's tied for the highest disapproval rating among all the candidates, along with Johnson.
Analysts have questioned whether the former congressman from Georgia's campaign would survive the flurry of negative press in the wake of his Ryan criticism - his bid, even from a former speaker of the House with deep ties to many influential party leaders, was seen as quixotic from the start.
But as Gingrich falls, Herman Cain rises. The former CEO of Godfather's Pizza has seen his name identification nearly double in the last month: from 21 percent to 37 percent. He's likely gained traction in part after a sterling performance at the first GOP presidential debate in early May, an effort that won him the debate according to some pundits.
He's also popular among the Republicans who know him: 27 percent hold a strongly favorable view, compared to just three percent who view him very unfavorably. The positive intensity score of 24 points is the highest in the GOP field.
Also gaining in name ID is former Minnesota Gov. Tim Pawlenty. He's been seen as one of the race's front-runners despite his relatively low name recognition, but Gallup reports half the party now knows who he is. That's a 10-point jump from last month.
The poll of Republicans and Republican-leaning independents living in all 50 U.S.
states and the District of Columbia was conducted as part of Gallup Daily tracking from May 16-29, 2011. Questions asking about the 10 potential candidates were rotated among randomly selected samples of Republicans each night and over the two-week period, each candidate was rated by a minimum of 1,500 Republicans and Republican-leaning independents.
The survey carries a margin of error of +/- 3 percentage points for the overall ratings of each potential candidate and for the Positive Intensity Score for each candidate, the maximum margin of sampling error varies depending on the size of the group recognizing the candidate.