You have raised similar issues on this blog, but the question I have is why? Why has the level of political civility apparently declined? Why is there such an attack on women's rights, people of color, etc. as we have seen in places like Arizona?
I wonder if it is not two issues. First, and I think you have disagreed with me about this before, I think that the United States is more of a conservative-leaning nation. That when pressed, the nation has not pushed social reform issues further than it could have because of inherent conservative tendencies. I think of Gordon Wood's discussion of the Constitution, Eric Foner's work on Recontruction, historians who assess the impact of the Progressive movement and the Great Depression.
Second, I wonder how the frontier mythology on which the nation is contracted is partly at play here as well. In other words, I trace much of the current retrenchment, xenophobia and the like to 9/11. Turner argued that the "consolidating agent" on the frontier was the fear of Indian attack. So, in this way, 9/11 resembles the colonists' and nation's response to things like the Pequot War or Pearl Harbor. Rather than bringing out the best in people, there is a backlash - sending Pequots into slavery in the Caribbean, interning Japanese American citizens, endorsing torture.
For those who may not know, Gordon Wood is one of the preeminent scholars of the American Revolution, and he argued, among other things, that the constitution represented a fundamentally conservative retrenchment against the excesses of direct democracy and the rather flippant ideas of the Declaration of Independence. For Wood, some of the freedoms that Americans realize after 1787 are almost accidental--in that the founders really didn't intend for those terms and ideas to apply to the "common man."
FJ Turner wrote a very influential article called "The Significance of the Frontier in American History," that redefined American history at the time. He argued that the frontier, or availability of "free land" defined America and encouraged the creation of American ideas like individualism, egalitarianism, and even our form of democracy. And, as CIL notes, the identification of the Indian as "other" is critical to that American development.