Northerners like to poke fun at southerners. No instance for that was clearer than when a Public Policy Polling poll published last week (pdf) showed that more Alabama and Mississippi Republicans believe President Obama is a Muslim than think he's Christian. The headlines in much of the northern-based media were predictable. As David Graham put it in the Atlantic, the Huffington Post, Talking Points Memo and Daily Kos resorted to deadpan humor and "smirking at those southern bumpkins".

Now, I am as much of a northern elitist as the next Yankee. I grew up in New York City and was indoctrinated by history professors whose college theses revolved around the growth of the American Labor party in the 1930s. But the fact of the matter is that the views of the voters in Alabama and Mississippi are simply not that different from northerners on questions revolving around Obama's citizenship and religious affiliation.

This week, Public Policy Polling released a poll of Illinois Republicans (pdf) and found that more of them (39%) believe Obama is a Muslim than a Christian (24%). The same percentage of Illinois Republicans offered the opinion that Obama was not born in the United States (36%) as those who said he was (36%).

Keep in mind that Barack Obama served as state senator in Illinois from 1997 to 2004, United States senator from 2005 to 2008, and currently maintains a residence in the state. Obama also won an almost unheard-of 40% of the Illinois Republican vote in his run for Senate in 2004.

So, we have voters who know Obama well, seemed willing to vote for him eight years ago, and are now offering views that are, by any measure, false (or, as my New York self would put it: pure trash). What the heck is going on here? Is it that northern Republicans are just as dumb as southern Republicans? No.

Before President Obama provided his actual birth certificate, political science professor John Sides discovered that many Republicans with high education levels were willing to go on the record and tell a pollster that Obama was not born in the United States. The percentage of well-educated people who said so rose at a much higher rate, during the Obama presidency, than it did among people who were less educated. The same trend (in reverse) was seen in the percentage who expressed the opinion that Obama was a Christian. How could this be?

Brendan Nyhan (a brilliant professor at my alma mater) posits that it's voters who are more tuned into news outlets (which is correlated with higher levels of education, though not the same thing as being well-educated) who are more likely to pick up misinformation, if it's against an unliked person. Listening more often to talking heads who give a wink and a nod to the conspiracy theories about someone you don't like is more likely to lead you to repeat that theory.

Put another way, the person who dropped out of high school and listens to no news isn't that much more likely to say Obama is a Muslim than is the Ivy League elitist who listens to Republican talking heads all the time.

The belief that Obama is something other than a Christian born in the United States has everything to do with ideology. Republicans are just perturbed beyond belief by Obama, and when you offer them a prompt about said person, they are likely to say anything that might be seen as a negative. It's as Julian Sanchez (via Graham) put it, "symbolic belief":

"Propositions you profess publicly, maybe even sincerely believe, you believe; even while, on another level, there's some part of you that knows better."

Symbolic belief affects liberal and conservatives, Democrats and Republicans, northerners and southerners. Remember when a poll produced the result that 35% of Democrats believed that George W Bush knew about the 9/11 attacks in advance? No serious commentator (outside of a few conspiracy theorists) held that opinion, but more than a third of polled Democrats were willing to say so.

Now check out these graphs from Public Policy Polling on the answers revolving around Obama being a Christian and a natural-born citizen, among Illinois Republicans. It's pretty much a straight line from the most conservative to the most liberal on those who say Obama is a Muslim and not a citizen.

Graph: Harry J Enten/guardiannews.com

In fact, the absolute correlation in both graphs is a near perfect 0.99 (that is, the relationship is very strong). Those who are most conservative are most likely to say Obama is a Muslim and not born in the United States, while the most liberal are least likely to state these positions.

Graph: Harry J Enten/guardiannews.com

The same relationship is found in the Alabama and Mississippi data, as this Mississippi graph illustrates. (Note that there aren't many very liberal Republican primary voters, so don't pay too much attention to the steep drop-off.)

Graph: Harry J Enten/guardiannews.com

Southern voters were more inclined to have an extreme dislike for Obama from the outset, so the percentage believing that Obama is a Muslim among each ideological group is somewhat higher in the south, but the trend, from most conservative to most liberal, is exactly the same as in Illinois.

So, what should take away from this data? When you read this polling data about Obama being a Muslim, understand what it's actually telling you. It's fascinating from an ideological standpoint (that is, people are willing to say stuff they probably don't believe, deep down), but nothing more.

Most Republicans probably don't believe Obama is a Muslim. They just really, really don't like him.