PRINCETON, NJ -- Mitt Romney (17%) and Sarah Palin (15%) now lead a smaller field of potential Republican presidential candidates in rank-and-file Republicans' preferences for the party's 2012 nominee. Ron Paul, Newt Gingrich, and Herman Cain essentially tie for third, with Cain registering 8% support in his initial inclusion in Gallup "trial heat" polling. Notably, 22% of Republicans do not have a preference at this point.

The May 20-24 poll is the first update of Republican nomination preferences after a recent flurry of activity in the race for the 2012 nomination, with several formally declaring their presidential candidacies, including Paul, Gingrich, Tim Pawlenty, and Cain.

Perhaps as significant were the decisions by Mike Huckabee, Donald Trump, and Mitch Daniels to forgo the race. In Gallup's April update, Huckabee and Trump were the co-leaders, with Huckabee placing first in the other Gallup updates this year.

Of the 10 candidates included in the newly reduced list, 7 have either officially announced their candidacies or established exploratory committees. Jon Huntsman and Michele Bachmann are nearing decisions and are expected to get in the race, while Palin's status as a candidate is less certain.

Re-allocating Palin supporters' votes to the candidate who is their second choice gives a sense of where current preferences would stand without Palin in the mix. Under this scenario, Romney leads with 19%, followed by Gingrich and Paul with 12% each.

Romney's and Palin's status at the top of the field is owing in large part to their high name identification among rank-and-file Republicans. Gingrich and Paul are also well-known among the party base. Cain, on the other hand, is far less well-known, but he has generated a strong positive reaction among those who do know him, which allows him to place ahead of slightly better-known candidates such as Bachmann, Pawlenty, and Santorum.

Romney's Support Varies by Education

Romney's appeal is much greater among college graduates (25%) than nongraduates (13%). Palin, meanwhile, fares better among nongraduates (18%) than college graduates (8%). The remaining candidates have fairly similar support by education.

Romney and Palin generally do better among conservatives than liberals and moderates. Paul is competitive with Romney and Palin for the top spot among liberals and moderates, though even combined, these groups make up a much smaller segment of the Republican base than conservatives do.

Further evidence that Paul's support generally lies outside the Republican mainstream is that Republican-leaning independents are twice as likely to support him as are those who identify outright as Republicans. Romney and Palin lead among the larger group of Republican identifiers.

Romney is the leading candidate among churchgoing Republicans, at 19%. Among Republicans who identify as Protestant or some other Christian religion (other than Catholic or Mormon), his support is 15%, tying him with Palin as the leader among that group. This is notable given that some think Romney's Mormon faith could hurt his support among Protestants.

Implications

In the short term, Romney and Palin seem to have benefited most from several prominent potential Republican candidates' decisions not to run for president. Should Palin follow suit and not enter the race, Romney would be the clear front-runner, but arguably the weakest front-runner in any recent Republican nomination campaign.

As such, the race remains wide open, which is underscored by the fact that one in five Republicans currently have no preference.

Track every angle of the presidential race on Gallup.com's Election 2012 page.