I'm British, but I find myself more and more talking about American politics and the American legal system. Why is this? It's not because I love America or want to move there, or that the people in the American system are in any sense notable. There's the dull practical reason that this is the internet and that the Americans own it, so it's easier to keep up to date about the states than the UK. But the key reason is different:
America has principles. Note not American politicians, that's not true, but the nation itself. If someone does something stupid in the UK you can argue against it and you can try and apeal to the idea of human rights and ancient liberty... but that has no legal or historical force whatever. There is a human rights act in the UK that aims to throw out bad and illiberal law, but it has no teeth whatever and is under constant attack from right wing newspapers. When the EU court of human rights told the government that their DNA database was totally illegal ... they simply ignored it and made cosmetic changes.
In America there is a constitution, there are principles of law. Now these are by no means absolute, nor are they universally enforced. The universal rights of the 14th Amendment are laughed off as irrelevant or ignored in the gay marriage debate. The First (free speech) and Fourth (no unreasonable search and seizure) Amendments are totally shot following the war on terror. But they still exist and the constitution still has at least some authority.
Why do I talk about America then? Because in the UK whenever something totally illiberal comes up, (42 days pre-charge detention, DNA database, internet patrols) one has to genuinely ask the people if that's the sort of society they want to live in. And sadly the right wing press tells them that they do. In America, when Guantanamo or wiretapping or the teaching of evolution or gay marrage or anything else comes up in politics, you dont have to ask if the people want to live in an illiberal society. They aren't allowed. It sounds a very strange idea, but America is not designed to be a democracy, the people are not sovereign, the constitution is. If politicians do something illiberal one cannot ask if this is what we want America to become, legally the only way to do it is either to alter the constitution (either in wording or interpretation) or to have a glorious revolution and start America again on a new foundation of bigotry and wiretapping.
This is important in debates becasue it makes things so much easier, there can be no debate about what America should be in the ordinary course of politics. When you want to change the foundations of politics you must get the supreme court behind you and jump through endless hoops and generally make it obvious that that is what you are doing. In the UK you can change the political landscape with a vote hardly anyone turns up to. Parliment is soverign and has no oversight on whatever stupid damn thing they want to do.
This is not to say that the constitution is a final arbiter of morality, there are a lot of things wrong with it. But it is a very well designed starting point for good politics. The founding fathers left extensive writings to tell us how to interpret the constitution and the rights they provide are vital. And there is danger in undermining it, recently the liberal blogosphere has been churning the idea of getting the supreme court to reduce the protection of the Second Amendment, they want to give states the right to outlaw and control guns in a way that congress is not allowed to do. This is a bad bad idea. Even if you believe that this would be a good idea insofar as its effect on gun law it is still very very dangerous to mess with the constitution. Once the clear meaning of the Amendment is altered to strip it of all power there is nothing to stop the process being repeated for the rest of the constitution. The First Amendment say, or the Fourth, or the Fifth. If congress cant inflict cruel or unusual punishment on you why not let the states?
In the UK there is nothing to stop such an idea gaining traction, there is no grand principle to appeal to to stop it happening. But when something like this happens in America you can have all the popular support and intellectual underpinning for a bad law that you like, but the Supreme court will still throw it out, you can still argue that this violates what America is about, what Jefferson would have done. And unlike in the UK if the person you are arguing with doesn't want to follow what Jefferson would have done (and fair play to him, there's no reason he shouldn't want to free himself of the dictates of a dead old white guy), there is a simple remedy: either change the constitution, start the glorious revolution and begin America anew, or just up and leave. America is a nation defined by the founding fathers, I think they were good people, but you are free to disagree. Just in the normal course of politics it is their political and moral standards things are held against. If you dont like that, feel free to move to the UK, here things are measured by the moral standards of Murdoch inc.