Brian Kilmeade gave more than 16 minutes of airtime on his Fox News Radio show to birther Jack Cashill to push conspiracy theories about Barack Obama and his upbringing.

Cashill, author of Deconstructing Obama (more about the book here), told Kilmeade that Obama has constructed a “big lie” about the first few years of his life; Bill Ayers wrote Dreams From My Father; Obama is “using” Michelle Obama and his marriage as a political calculation; and a reporter should ask Obama, “where's the birth certificate?”

On Obama's upbringing, Cashill has previously claimed that Frank Marshall Davis “quite possibly” had sex with an “underage Obama” and Barack Sr. isn't Obama's father. If you need more evidence that Cashill is untethered from reality, just take a glance at his columns hosted at birther center WorldNetDaily.

At the conclusion of the interview, Kilmeade said: “Jack Cashill, good luck with your book. You have some interesting thoughts, and research. See what you think of it.”

Kilmeade's promotion of Cashill comes just two weeks after Kilmeade suggested people shouldn't bring up President Obama's upbringing. In response to Mike Huckabee's false claim that Obama grew up in Kenya, Kilmeade said: “I just think that's a non-starter with any president. Why would you even bring up the president's upbringing? You never brought it up with Bush, Clinton, Carter. Forget it.”

Kilmeade's suggestion smacked of hypocrisy since Kilmeade was one of the first national media figures to pickup the false story that Obama was educated in a madrassa. Kilmeade's Fox & Friends, along with the rest of Fox News, has been home to suggestions that Obama lacks a valid birth certificate and wasn't born in the United States.

And now he's giving 16 minutes of airtime to a guy like Jack Cashill.

Kilmeade's interview below: