Every country has its faults and its priorities, and every country has its own circumstances to deal with. For instance, it's easy to avoid racial issues when you have a racially homogenous population. Britain was over 90% white in 2001 (http://en.wikipedia.org/wiki/Demography_of_the_United_Kingdo... US was about 75% in 2008 (http://en.wikipedia.org/wiki/Demography_of_the_United_States...). It's easier to maintain infrastructure when you have one and 1/4 small, densely populated islands, rather than a vast, sparsely-populated continent with clusters up and down either coast.
Yes, we have a high prison population. And for many reasons that's not justified. But it's also largely because our circumstances are different from yours, and there's no evidence yet that, given the chance, Britain would handle those circumstances any better than the US.
You want to talk about civil liberties, when Americans still hold inviolate some of the old English civil liberties that old England has now deemed obsolete? You want to talk about race relations when members of the BNP--of which there is no American equivalent with any comparable level of support--represent your country in the European Parliament? Trust me--as much as you may worry about or pity the Americans, the feeling is quite mutual.