In the case of these websites, what law is being broken? And where? And does Spanish law have a right to tell an American organisation what to do? I don't think so!
Surely, the activities of people IN Spain (viewing the Internet, writing for websites) is an internal matter for the legal processes there.
But beyond Spain they have limited powers.
Of course, nation states choose at what level they are going to intervene in censoring online material. For example, grotesque and brutal child-porn would obviously invite intervention on its perpetrators within most countries.
But what about freedom of speech and the right to engage in political debate?
Presumably the US Government either has - or is considering - granting itself greater powers to ban websites on its systems which contravene certain criteria (specific terrorist activities for instance?). In such case, presumably the Government of another country can request the removal of a site on those grounds, should the US Government at its discretion be willing to intervene.
But it is a very dangerous area. One persons subversive is another persons freedom fighter. Would the dissidents in the old Soviet Union have been regarded as subversives or heroes?
What about Chinese dissidents today?
Would the Christians in the early Roman Empire have had their websites banned if they'd been online in those days?
Is the IRA a group of freedom fighters or are they enemies of the state?
I'm shortly planning to develop a site at Mugabe.info to invite open dialogue about Robert Mugabe of Zimbabwe. I'm interested in the right of open discussion and freedom of speech : I don't seek a partisan approach either in favour of Mugabe or against him.
Personally, I favour this freedom of speech being afforded even to organisations I am opposed to.
The most dangerous precedents for the future of the Internet include the claims of governments to censor what people may or may not access, and the claims of government to access the private mail and computers of citizens who legitimately demand some privacy.
Therefore - notwithstanding the war on terror - I hope the US Govt and US courts would resist moves to "take down" these websites unless there was specific operational reference / incitement to terrorist activities.
Holding a different opinion to somebody is not, in itself, a sufficient reason to ban their freedom of speech.
As for ICANN : well, it refuses even to regulate its own registries or accredited registrars... how then, can we expect it to regulate the rest of the world!