The key to the situation, I believe, lies in the fact that the extradition of these terrorists and enablers of terrorists to the US will still take months.
The US Presidential election is due to take place in November 2012. It would be naïve of Barack Obama not to look across the Atlantic at resurgent patriotic movements like, in the UK, the English Defence League and British Freedom. Powered by disaffected blue-collar voters, these diverse movements spread from the political centre to embrace and transcend left and right. So while politicians always feel compelled to appear all things to all people at election time, doing so is essential to Obama's survival now.
Hamza et al must be a gift to the President. He can appeal to the right-wingers by being seen to be acting to get the masterminds of 9/11 into American jails around election-time; and he can give subtle signals to left-wingers that when Abu’s army is put on trial, it will not them but American foreign policy in the dock. In short, he can burn the flag he flies.
Meanwhile, back in Blighty, the only people who are fooled into thinking that this is a victory against the fascist oppression of European "justice" are those who fool themselves. British politicians got this ostensible victory by bowing and scraping to their EU masters: had there been any political will to have justice done upon Hamza and the other enablers of 9/11, it would have been done years ago.