A recent poll showed that about 18% of Americans think that President Obama follows the Muslim faith, and only one in three identifies him as a Christian. During the campaign, his attendance at Reverend Wright’s church, a Christian church, was a significant issue. that might have driven home the point that he was Christian. In his books and interviews Obama declares he is a Christian. If that isn’t enough, Obama drinks alcohol, which Muslims do not. I suppose no one knows with absolute certainty what is in President Obama’s heart-of-hearts, but there is no objective evidence to claim he is a Muslim. So where do people get the idea?

One explanation is that the claim is repeated in Internet spam, and repetition feeds the belief. The percentage thinking he is Muslim has risen since he took office, from 11 percent then to about 20 percent now. So if there is a campaign of spreading misinformation, it must have picked up. But if so, is it so difficult to find evidence of the claim being spread? I receive as much political e-mail as anyone, but I’ve never received claims of Obama being Muslim. That doesn’t disprove it, but it casts doubt on it being a massive orchestrated campaign. You can’t keep a massive orchestrated campaign a secret. Still, there are some open proclamations of doubt of Obama’s Christianity to point to, such as the Reverend Franklin Grahams claim that “Obama was born a Muslim.”

Another explanation of the mistaken understanding is that Obama has not joined a church in Washington nor regularly attended services. However, President Reagan did not regularly attend church services, and was as private about religion as Obama. That didn’t cast doubt upon Reagan’s Christianity. Moreover, not joining a christian church is better evidence of agnosticism than Muslim belief.

There are past cases of unjustified beliefs to consider as we ponder the reasons. When Obama was elected president, polls showed that about half the people voting for him thought that Republicans controlled Congress, while few McCain voters shared that false belief. McCain supporters were aware that Democrats had taken over control of Congress in 2006. So is the widespread erroneous belief of Democrats evidence of an orchestrated campaign of misinformation? Perhaps evil left-wingers projected bad information about Congress, just as evil right-wingers are now supposedly circulating false information about Obama’s religious beliefs.

Back near the start of the Iraq war, a significant percentage of the public believed that Saddam was linked to 9/11. The Bush Administration had never made that claim, although they claimed that Saddam had supported terrorist causes, which he in fact had. The Left claimed that Republicans must have had a secret campaign of disinformation, because surely it couldn’t be a coincidence that such an unsubstantiated belief was widespread. If false beliefs require orchestration, then that would tell us that the belief that Republicans controlled Congress must have been the result of a propaganda effort as well.

None of these cases of widespread misinformation are supported by evidence of major disinformation campaigns, by e-mail or otherwise. I don’t doubt that someone sent out e-mail opining on each of these subjects. The Internet is somewhere host to every false thing one can imagine. However, most political spam has little effect. They tend to convince the already-convinced, and not many beyond that.

What is really at work is the confirmation fallacy. When a person becomes pre-disposed to believe something, then that person values all confirming evidence, and discards or downplays all the evidence to the contrary. In the case of Obama’s religion, his Cairo speech apologizing for US actions in the Middle East, his slacking off of support for Israel and insulting the Israeli Prime Minister, his failure to vigorously condemn the Iranians or support the Iranian protesters, and his recent comments supporting the right to build the Ground Zero Mosque are all consistent with an unproved theory that Obama is a Muslim. The contrary evidence is downplayed as relatively insignificant.

Obama voters were predisposed to think that Republicans had screwed up everything, and Republican control of Congress is consistent with that broad belief. Americans were pre-disposed to think Saddam was a radical anti-American so his being involved in 9/11 would “make sense.” Obama’s apparent favoring Muslim causes makes it “logical” to believe he does so because he is a Muslim. Some people will inevitably attempt to press their unproven theories, but that is more an effect of the belief rather than a cause. Belief in a theory grows as more people become pre-disposed to it and to disregard counter evidence.

The short answer to why some people believe Obama is a Muslim is they have figured it out on their own. Then they look for confirming evidence while ignoring contrary evidence.