Birthers make a majority among those voters who say they’re likely to participate in a Republican primary next year. 51% say they don’t think Barack Obama was born in the United States to just 28% who firmly believe that he was and 21% who are unsure. The GOP birther majority is a new development. The last time PPP tested this question nationally, in August of 2009, only 44% of Republicans said they thought Obama was born outside the country while 36% said that he definitely was born in the United States. If anything birtherism is on the rise.

How does this impact Romney? Well among the 49% of GOP primary voters who either think Obama was born in the United States or aren’t sure, Romney’s the first choice to be the 2012 nominee by a good amount, getting 23% to 16% for Mike Huckabee, 11% for Sarah Palin, and 10% for Newt Gingrich. But with the birther majority he’s in a distant fourth place at 11%, with Mike Huckabee at 24%, Sarah Palin at 19%, and Newt Gingrich at 14% all ahead of him. That pushes him into a second place finish overall at 17% with Mike Huckabee again leading the way this month at 20%. Palin’s third with 15%, followed by Gingrich at 12%, Ron Paul at 8%, Mitch Daniels and Tim Pawlenty at 4%, and John Thune at 1%.

There is really a remarkable divide in how the birther and non-birther wings of the GOP view Sarah Palin. With the birthers she is a beloved figure, scoring an 83/12 favorability rating. Non-birthers are almost evenly divided on her with 47% rating her positively and 40% unfavorably.

This is yet another poll where we find Palin with the highest favorability among Republican primary voters but still lagging in the horse race. 65% have a positive opinion of her compared to 58% for Huckabee and 55% for Romney and Gingrich. Her problem is that even though they like her, few GOP voters think Palin’s qualified to be President. Asked whether she’s more qualified to be President or Vice President, only 29% of voters place her in the top spot compared to 46% who say she’d be a more appropriate number 2.

On the President/Vice President qualification question only Romney reaches a majority on the qualified to be President card with 50% saying he’s most equipped for that position to 24% who think he’d make a better Vice President. Huckabee has 44% who think he’s suited to be President to 28% who think he’d fit more in the VP slot, and Gingrich has 27% who consider him more Presidential to 37% that think he’s more Vice Presidential.

It’s a clear sign of weakness for the GOP field that only one of its leading potential candidates is considered to be Presidential material even by a majority of the party base.

Full results here