According to Sharon Begley's article at Newsweek, "Lies of Mass Destruction," people are susceptible to upside down reasoning. She cites a large team of researchers who studied the people who believe the lie that Saddam Hussein caused 9/11. The researchers concluded that these believers believed that lie because the U.S. invaded Iraq. They refer to this upside-down process as "inferred justification." Begley sums it up:

Inferred justification is a sort of backward chain of reasoning. You start with something you believe strongly (the invasion of Iraq was the right move) and work backward to find support for it (Saddam was behind 9/11). "For these voters," says Hoffman, "the sheer fact that we were engaged in war led to a post-hoc search for a justification for that war."

The researchers published their findings in a paper entitled "There Must Be a Reason”: Osama, Saddam, and Inferred Justification." Here's an excerpt from Sociological Inquiry.

The primary causal agent for misperception is not the presence or absence of correct information . . . Our explanation draws on a psychological model of information processing that scholars have labeled motivated reasoning. This model envisions respondents as processing and responding to information defensively, accepting and seeking out confirming information, while ignoring, discrediting the source of, or arguing against the

substance of contrary information. Motivated reasoning is a descendant of the social psychological theory of cognitive dissonance, which posits an unconscious impulse to relieve cognitive tension when a respondent is presented with information that contradicts preexisting beliefs or preferences. Recent literature on motivated reasoning builds on cognitive dissonance theory to explain how citizens relieve cognitive dissonance: they avoid inconsistency, ignore challenging information altogether, discredit the information source, or argue substantively against the challenge. The process of substantive counterarguing is especially consequential, as the cognitive exercise of generating counterarguments often has the ironic effect of solidifying and strengthening the original opinion leading to entrenched, OSAMA, SADDAM, AND INFERRED JUSTIFICATION polarized attitudes. This confirmation bias means that people value evidence that confirms their previously held beliefs more highly than evidence that contradicts them, regardless of the source.

In her article, Begley suggests that the current health care debate stems from the same cognitive vulnerabilities.

There are legitimate, fact-based reasons to oppose health-care reform. But some of the loudest opposition is the result of confirmatory bias, cognitive dissonance, and other examples of mental processes that have gone off the rails.