Leon Festinger's "Theory of Cognitive Dissonance", 1957 focuses on how humans strive for internal consistency. When inconsistency (dissonance) is experienced, individuals largely become psychologically distressed.

• An environmentalist purchases a car with bad gas mileage or a larger than necessary house. (me). You justify the car in that it can help pull your neighbors out of the snow when they are stuck and the house is an investment in your families future.
• Fred works in an office. After work, he decides to steal a few office supplies. Even though he knows it's wrong, and he could get in trouble, he decides he deserves them for the 'hard work' he's been putting in recently.
• Gilbert stays in shape. In one day, he ends up eating a fast food meal for lunch, and a pizza for dinner. He decides that heÕll just burn off the extra calories anyway, as he exercises for an hour every day. Anyway, he had a small breakfast so needs to Ômake up for itÕ.
• Laura really values a man with a good sense of humour. When she first met her boyfriend Adam, he seemed funny Ð but actually heÕs really boring. Rather than feel dissonance, she decides to leave him for a funnier man.
• Bill knows that smoking is bad but likes to smoke. He says it relaxes him.
• College students who put themselves through hazing to join a fraternity.

"When pollsters ask Republicans and Democrats whether the president can do anything about high gas prices, the answers reflect the usual partisan divisions in the country. About two-thirds of Republicans say the president can do something about high gas prices, and about two-thirds of Democrats say he can't.

But six years ago, with a Republican president in the White House, the numbers were reversed: Three-fourths of Democrats said President Bush could do something about high gas prices, while the majority of Republicans said gas prices were clearly outside the president's control.

The flipped perceptions on gas prices isn't an aberration, said Dartmouth College political scientist Brendan Nyhan. On a range of issues, partisans seem partial to their political loyalties over the facts. When those loyalties demand changing their views of the facts, he said, partisans seem willing to throw even consistency overboard.

Nyhan cited the work of political commentator Jonathan Chait, who has drawn a contrast between the upcoming 2012 election between President Obama and the likely Republican nominee, former Massachusetts Gov. Mitt Romney, and the 2004 election between President Bush and John Kerry, the Democratic senator from Massachusetts.

"Last time it was Republicans who were against a flip-flopping, out-of-touch elitist from Massachusetts, and now it's Democrats," Nyhan said.

Along with Jason Reifler at Georgia State University, Nyhan said, he's exploring the possibility that partisans reject facts because they produce cognitive dissonance -- the psychological experience of having to hold inconsistent ideas in one's head. When Democrats hear the argument that the president can do something about high gas prices, that produces dissonance because it clashes with the loyalties these voters feel toward Obama. The same thing happens when Republicans hear that Obama cannot be held responsible for high gas prices -- the information challenges their dislike of the president.

Nyhan and Reifler hypothesized that partisans reject such information not because they're against the facts, but because it's painful. That notion suggested a possible solution: If partisans were made to feel better about themselves -- if they received a little image and ego boost -- could this help them more easily absorb the "blow" of information that threatens their pre-existing views?

Nyhan said that ongoing -- and as yet, unpublished -- research was showing the technique could be effective. The researchers had voters think of times in their lives when they had done something very positive and found that, fortified by this positive memory, voters were more willing to take in information that challenged their pre-existing views.
Source: NPR.org - Partisan Psychology: Why Are People Partial To Political Loyalties Over Facts?, Published: May 09, 2012 by Shankar Vedantam

Steele (1988) argues that the main cause of dissonance is not necessarily the difference between actions and beliefs, but the resulting degradation of self-image.
Steele, C. M. (1988). The psychology of self-affirmation: Sustaining the integrity of the self. In L. Berkowitz (Ed.) Advances in experimental social psychology (Vol. 21, pp. 261-302). New York: Academic Press.

Many people with extreme, many times contradictory, views have self esteem issues. This goes for things like religion and racism as well as politics.

I remember reading a theory that the racism and conservative Christianity that grew in the South after the Civil War was in part caused by lack of self esteem, from loosing the war and the rise of the industrialized North. I can't find the source of that article now.

In "Low Self-Esteem and Its Connection to Cognitive Dissonance" Daniel A. Bochner, Ph.D. discuses a variety of topics.
A victim of Stockholm Syndrome is a person who starts to believe and espouse the very different values of their captors after being held and tortured. In these cases, only the possibility that the captors' beliefs are correct and momentously important can allow the victim to make sense of how badly traumatized they have been. It becomes more important in the psyche to feel there is a good reason for the chaotic abuse that has occurred than it is to maintain the belief that the captors are criminal or hateful. The need to turn traumatizing chaos into something seemingly logical is the paramount factor in the development of low self-esteem. When we have been traumatized, the explanation we give ourselves to make sense of the torture we have endured almost always makes it our own fault or responsibility. If the trauma was our own fault then it would seem to be within our control. If things are within our control, on their surface they seem to be less threatening.

Links:
Cognitive dissonance - Wikipedia
Oil, Cognitive Dissonance, and American Politics " Sociological Images
Cognitive Dissonance and Politics : The Frontal Cortex
Marriage: Demonstrating the Value of Cognitive Dissonance, Every Day | Harpy's Review | Big Think
Cognitive Dissonance, Halo Effects, and the Self-Esteem Trap
Cognitive Dissonance Theory
Cognitive dissonance & self-esteem - Later On (Ben Franklin story)