Trump says birther comments will help Perry in GOP primary

"My gut tells me a couple of things. Number 1, you know it took a long time to produce this certificate and when it came out, as you know, you check out the Internet, many people say it is not real. Okay? It's a forgery," Trump said. "And the other thing is, nobody has been able to see the day of his birth, they had twins born, they had the other one born. Nobody has been able to find any records that he was born in that hospital."

During his brief flirtation with a presidential run, Trump said he had launched an investigation into the validity of Obama's birth certificate and his people "cannot believe what they're finding," but he has never revealed any findings.

Perry said earlier Wednesday that he "had no doubt" about Obama's citizenship and implied that his earlier remarks questioning the authenticity of the president's birth certificate were made in jest.

“Look, it’s fun to, you know, lighten up a little bit,” Perry told Bay News 9 on Sunday.

But during a CNBC interview earlier this week, Perry said that "I don't have any idea" if the certificate was authentic and said "it's a good issue to keep alive."

Republicans worry that Perry could be delegitimizing his campaign by associating it with birther rumors, which have been widely discredited. The campaign has struggled to move coverage away from the issue and toward his flat tax plan announced earlier this week.