I think it will definitely chip away at the surveys. It’s sort of an inexact science because if someone calls you and says, “Do you believe x?”, the mere fact that someone is calling you on the phone to ask suggests that both points of view on the issue are legitimate. So the mere act of taking a survey sometimes causes respondents to embrace the dissident opinion. But now that the birth certificate is out there, most people who followed the issue casually will know: “OK, this is now a discredited opinion. It’s the equivalent of thinking the moon landing was a hoax or thinking the world is flat. My neighbors are telling me this has been settled and they’re starting to make fun of me for talking about it, so I’m going to move on.”

If a pollster looking at birtherism calls a conservative who hates Obama, and the respondent knows that the negative answer is that the president was born abroad, might that dynamic explain some of the poll results? The same phenomenon might have been in play among Democrats in 2007 or 2008 when there were pollsters asking, “Did Bush know about 9/11 in advance?”

There are people who are polarized who will simply choose the most radical answer to any question that aligns with their ideological point of view. In the years immediately after 2003 when the Iraq war began, you could say anything about Bush in the left-wing press, and you’d find people who would say, “Oh yes, that’s true. He’s a theocrat, he’s a fascist, he’s a Nazi.” Yes, it’s terrible what they’re saying about Obama, but I think people have short memories and they don’t remember how bad the things that were said about Bush were.

I also think it’s true that birtherism is a symbolic issue. The belief that Obama was not born in the United States is symbolic of a  gut-level feeling that Obama is somehow an illegitimate American, that his politics are illegitimate, that he’s trying to turn the United States into something that is not American, that he’s against capitalism, that he’s against Christianity, that he hates whites. Some people have swallowed all these points of view. Birtherism is a short-hand for saying, “He’s not a real American.”

Turning to 9/11, do you think there are legitimate unanswered questions about the event that deserve investigation?

There are certain quiet scandals about 9/11 that have nothing to do with any inside job that haven’t been talked about very much. One of the interesting things is the collapse of World Trade Center 7, which fell around 5 p.m. on 9/11 because of a fire. Truthers will tell you it collapsed because of an explosion in the building, and they will show you videos and say the footage proves it was controlled demolition. Now, National Institutes of Standards and Technology put out a report explaining how that building fell. It had nothing to do with explosives or anything like that. There was a progressive fire and one of the columns fell off the moorings and the building collapsed. However, it is to me an engineering disgrace that a modern, conventional, steel-frame skyscraper like WTC 7 — which was a huge building — collapsed due to what were essentially localized fires on just a few floors. I’m quite shocked it didn’t get more attention.

When in comes to the atmosphere in which trutherism emerged, it has been argued that there was good reason to mistrust the government. After Iraq, a lot of people believed the government had lied on a large scale about a matter of great importance. So why not suspect the government may be lying about other things too?

All conspiracy theories are based on a fundamental distrust of public institutions. In the case of 9/11 conspiracy theories, the original theories were created in late 2001. But when they really took off was 2003 and 2004 when it was discovered there were no WMDs in Iraq, and people did feel deceived. My own view is that it was a question of bad intelligence plus a U.S. government that was anxious to destroy the threat from Saddam Hussein.

What about the conspiracy theories in the 1990s surrounding Bill Clinton — like the long list of people that he and Hillary supposedly killed. What was going on there? Was it about mistrust of government?

Those are interesting. But the most enduring and powerfully embraced conspiracy theories are always epic in scale. They always involve control of the world or the world’s oil supply. If you look at conspiracy theories about 9/11, conspiracy theories about the new world order, about the United Nations, the Bilderbergs — even the birthers, who think Obama is a Manchurian candidate who wants to impose sharia or bring the U.S. into subservience of the U.N. — they tend to be epic in scale. Kind of like a Hollywood film. The reason that the Clinton-era conspiracy theories fizzled out pretty much after his presidency is that they didn’t have that romantic aspect. They all focused fairly narrowly on the machinations of political operatives.

Did you ever have success disabusing anyone of their conspiracy theory?

Not once. The reason is that when you debate a conspiracy theorist it’s like challenging an NFL football team to a game. Because conspiracy theorists have spent their lives memorizing every single detail necessary to win an argument. Even if you have the facts on your side in an abstract way, you’re not going to win an argument if you have to go look at Google or go to the library to rebut every single point. They have hundreds of little confusing bits of information that they can throw at you. Even if you bat away 99 of them, the 100th, if you don’t repute it immediately, they’ll say, “Ah ha! There’s an anomaly that you can’t explain.” The way they define the terms of the debate is that they just have to get you on one point, and then they have destroyed the validity of the conventional narrative.

The second thing is, it’s a cult. And you can’t disabuse a cult member of their beliefs, because it’s central to their identity. Hardcore conspiracy theorists are attached to their conspiracy theories with the same force of conviction that religious adherents are attached to their religions. You can’t rationally convince someone not to be a Christian or a Scientologist. That’s their identity, that’s who they are.