(AP Photo/Manuel Balce Ceneta, File) Donald Trump (Manuel Balce Ceneta/Associated Press)

Tony Fratto, a deputy press secretary under President George W. Bush, offered some useful advice via Twitter this morning to those of us in the media. “If you put Trump on TV, interview him, cover his clown act,” Fratto tweeted, “then you are part of it, too —  right there under the big tent yourself.” He’s right. But I have to poke my nose under the tent one more time to point something out.

The Republican Party’s most famous birther was at it again in an interview with ABC News’s Jonathan Karl on Sunday. He can’t seem to stop peddling the racist lie that President Obama was not born in the United States (and therefore is an illegal occupier of the Oval Office). When Karl asked him whether he still believed the president was not an American citizen, Trump replied, “I have no idea. I don’t know, was there a birth certificate? You tell me. You know, some people say that was not his birth certificate. I’m saying I don’t know. Nobody knows.”

Trump’s daft response triggered a repressed memory. According to an April 2011 interview, he absolutely should have an idea. When he rattled off a series of unanswered questions related to Obama’s birth on the Today Show, Meredith Vieira challenged him on how he knew enough to ask the questions:

You’ve been privy to all of this to know this?
Well, I have people that actually have been studying it and they cannot believe what they’re talking.
You have people now out there searching– I mean, in Hawaii
Absolutely. And they cannot believe what they’re finding. And I’m serious–

Remember Trump’s explosive press conference detailing these findings? Yeah, neither do I. And there’s a simple explanation for this: there never was one. And there will never be one.

Not that anyone believed that the 2012 Republican presidential nomination teaser was serious. Trump’s knack for showmanship over truth turns even the most naive reporter into a hardened skeptic.

That Trump is out there again waving the birther flag shouldn’t come as a surprise. But what continues to amaze me is that no grown-up with national stature in the GOP is willing to tell Trump and his birther acolytes to stuff it. Pity House Speaker John Boehner, Senate Minority Leader Mitch McConnell and Republican Party Chairman Reince Priebus (when he’s not doing the important work of railing against not-yet-made TV movies) haven’t seen fit to follow Fratto’s lead.

Follow Jonathan Capehart on Twitter.