Jonathan Haidt has done research on moral beliefs, and how they effect people's political beliefs. His book is fascinating, and explains a lot.
He has found people made decisions based on emotion (guided by "morals") first, and then justify them afterwards with their reason. But there is considerable variation on what those morals are.
He also found that conservatives can understand and state the views of liberals much more easily than liberals can state views of conservatives.
He has decided there seem to be five basic foundations for morality. From his website:
1) Care/harm: This foundation is related to our long evolution as mammals with attachment systems and an ability to feel (and dislike) the pain of others. It underlies virtues of kindness, gentleness, and nurturance.
2) Fairness/cheating: This foundation is related to the evolutionary process of reciprocal altruism. It generates ideas of justice, rights, and autonomy. [Note: In our original conception, Fairness included concerns about equality, which are more strongly endorsed by political liberals. However, as we reformulated the theory in 2011 based on new data, we emphasize proportionality, which is endorsed by everyone, but is more strongly endorsed by conservatives]
3) Loyalty/betrayal: This foundation is related to our long history as tribal creatures able to form shifting coalitions. It underlies virtues of patriotism and self-sacrifice for the group. It is active anytime people feel that it's "one for all, and all for one."
4) Authority/subversion: This foundation was shaped by our long primate history of hierarchical social interactions. It underlies virtues of leadership and followership, including deference to legitimate authority and respect for traditions.
5) Sanctity/degradation: This foundation was shaped by the psychology of disgust and contamination. It underlies religious notions of striving to live in an elevated, less carnal, more noble way. It underlies the widespread idea that the body is a temple which can be desecrated by immoral activities and contaminants (an idea not unique to religious traditions).
He found conservatives value each of these five areas mostly equally.
However liberals only value care/harm and fairness cheating!
Conservatives can state liberal views because they also value care/harm and fairness cheating.
Liberals are frequently baffled by conservative views, because they don't care anything about the other foundations of morality.
The theory explains a lot. Why do democrats not mind voter fraud, breaking immigration laws and so on? Because they literally don't value the authority of the law or Constitution- their other values supersede this.
The Loyalty/betrayal standard (or lack thereof) is especially relevant when you consider the left's love affair with Islam, and Obama giving Iran huge amounts of money. The left doesn't value our people and culture above those of hostile cultures and nations.
The fairness/cheating moral is interesting too- both conservatives and liberals value this, but in very different ways. Conservatives think this means giving people what the deserve or earn. Liberals think this means giving everyone the "same." This explains why conservatives usually don't mind social programs like SS, as the recipients supposedly pay into the system. Unearned benefits, like food stamps, tend to be looked down on.
Liberals on the other hand, will say things like "No one deserves to be hungry." Conservatives would reply "If you refuse to work you do deserve to be hungry." Our response varies because we value fairness differently.
Libertarians actually score just like liberals, except they don't care much about care/harm.
His website is here:
http://moralfoundations.org/He has a great book too, "The Righteous Mind."
Sorry for the wall of text, I just find this theory very useful- once you think about it, examples of this will pop up everywhere.
