Jon Terbush April 21, 2011, 1:19 PM

The belief that President Obama was not born in America may seem like a fringe issue, but within the Republican party, the view is fairly mainstream.

In a New York Times/CBS poll released on Thursday, a 45% plurality of Republican adults said they believe Obama was not born in the U.S. Additionally, 33% said Obama was born in America, while 22% said they weren’t sure.

That result is on par with a February PPP poll in which 51% of Republican voters thought Obama wasn’t born in the U.S., while 28% said he was.

Overall, only 57% of all adults think Obama was born in America, according to the New York Times/CBS survey. A full quarter (25%) of registered voters think he was born outside the U.S., while an additional 18% aren’t sure.

Skeptics have been railing for years that Obama was not born in the U.S., and is thus inelegible to serve as President. And though Hawaii has produced Obama’s certificate of live birth, and independent investigations have long since confirmed that Obama is in fact a U.S. citizen, the conspiracy theory hasn’t petered out. In fact, it’s actually become far more prevalent of late, with Donald Trump flogging the issue across the airwaves as he hypes a potential presidential bid.

What’s more, there’s evidence that playing to the GOP’s birther base has paid off for Trump. Trump has shot to the forefront of the GOP presidential field in the past few weeks on the heels of his media blitz, even leading the entire GOP field by a nine-point margin in a recent PPP poll.

The New York Times/CBS poll was conducted from April 15-20 among 1,224 adults nationwide, including 543 Republicans. The entire sample has a 3.0% margin of error, while the Republican subgroup has a margin of error of 4.0%.

Barack Obama, Birth Certificate, Birther, Polls, President, Republicans