Aside from a handful of candidates, the prospective GOP candidates are virtually unknown to voters. In a March AP/GfK poll, over half of all adults had no opinion about five potential candidates: Haley Barbour, Jon Huntsman, Mitch Daniels, Tim Pawlenty, and Rick Santorum. Nearly seven in ten didn't know Huntsman well enough to form an opinion of him.
Rep. Michele Bachmann (R-MN), who's said she will form a presidential exploratory committee this summer, was also relatively unknown, with 43% of adults saying they had no opinion of her.
Five of those six candidates were clustered at the very bottom of the CNN poll that Trump topped, with none of them garnering more than 5%. The poll did not include Huntsman.
At the same time, the leading vote-getters in that CNN survey are all prominent Republicans with very high name recognition; only 4% of respondents in the aforementioned AP/GfK poll didn't have an opinion of Palin. The problem for them is that Republican voters know who they are, and are apparently unimpressed by what they see.
Take Palin, for example. In the CNN poll, she came closest to Huckabee and Trump with 12% of the vote. But in the same poll, just 53% of Republicans said they thought she should run for president, while 47% said she should not.
And while she continues to be a favorite of conservative voters -- 83% of "very conservative" voters viewed her favorably in the latest PPP survey of the GOP race, far higher than the percentage who liked any of the other candidates -- there are signs that Republicans know how deeply unpopular she is with the overall electorate, and that she would have a monumental challenge in winning a general election. The current TPM Poll Average gives Obama a 52.5% to 37% lead over Palin in a hypothetical general election.
Voters also have their reservations about Romney and Gingrich, who polled just behind Palin in the CNN survey at 11% each.
The albatross around Romney's neck is the universal health care bill he sponsored and signed as governor of Massachusetts, a bill that became a framework for Obama's healthcare overhaul. In a March PPP poll, 61% of Republican voters said they would't be willing to vote for a candidate who supported a state-level bill that mandated that all people get health insurance. And in the same poll, only 51% of Republican voters said they viewed Romney favorably, while 29% viewed him unfavorably.
That poll also had bad news for Gingrich, as it found that only 50% of GOP voters had a favorable opinion of him, while nearly one-third (32%) had an unfavorable opinion of him.
Compare those favorability ratings to President Obama's. In a PPP survey released this week, half of all voters viewed him favorably, including 83% of Democrats.
So what about Trump?
With a popular reality TV series and a high public profile, he's certainly well known. In a March Gallup poll, 90% of respondents knew enough about the real estate mogul to have an opinion on him. Trump has further elevated that profile in recent weeks, appearing more frequently on talk and cable news shows than any other potential candidate.
Trump has also repeatedly flogged the misleading and discredited claims about Obama's citizenship, even going so far as to say he'd dispatched an investigative team to Hawaii. And with a big television platform to present those claims, Trump has quickly gained praise from the party's birther wing.
Looking over at the entire field, it's split distinctly into two groups: those who are unknown, and those who are known but not particularly liked. The unknowns currently poll, as expected, near the bottom, while the knowns cluster near the top.
Trump is just the latest among the well-known and, with Republican voters not so hot on their other choices, there was plenty of room for him to slide into the pack. However, as the primary race intensifies, and lesser known candidates raise their profiles, the field is certain to undergo some drastic changes.