Many are critical of the decision due to anti-Americanism, so I feel that I should address this first. I do not oppose the extradition because I am anti-American, because I'm not, nor because of the one-sided nature of the extradition treaty. I do so because the whole situation is wrong and, as supportive of the US as I am, there are times when they need a firm rebuke. Margaret Thatcher thought nothing of telephoning Reagan to give him a piece of her mind, and America and Reagan loved her for it. America does not want a lap dog ally, and it certainly doesn't benefit from having one. The US needs a strong and good friend which is honest with it, and good friends don't let friends behave like this.
Gary McKinnon has Aspergers Syndrome, whereby he does not understand the consequences of his actions. In many ways he is like a child in this regard, would we extradite a child? Although he is incredibly intelligent in certain ways, he does not understand things which seem obvious to us, and so the grounds of diminished responsibility can fairly be invoked.
There is also the motive factor. Gary hacked the government's computers for benign reasons, namely the research of space aliens, and it's therefore possible to claim also that his actions were deemed by him to be in the public interest. Should we charge Damian Green and his Home Office mole for their non-technical version of hacking?
There is also a legal point. Where was the crime allegedly commited? The law seems to suggest it was performed in the USA, but remotely from the UK, and that it is therefore the USA which prosecutes. However this principle isn't sustainable. If a website offers a service from one juristiction, but is accessed or retrieved from another, the second cannot realistically bring charges against the site owner but I understand that this is the case and that there are already such individuals - who must now avoid certain juristictions or face arrest. In these cases it has been gambling websites, legal in the host region but accessed by users where such activity is illegal, so there is some difference to the McKinnon case where the activity was illegal in both, but the question of judicial powers is the same. If we allow the principle of extradition for prosecution under a foreign country's law for virtual crime performed remotely from within the UK, there is no knowing where it may lead. Mr McKinnon was on British soil and so should be charged under British law.
But perhaps the biggest argument against the extradition is the usefulness of Gary McKinnon. By hacking so expertly into the government's computers, has he not shown the weaknesses of their security? Cyber attacks are an increasing risk - Russia uses them regularly - and hacking is a serious threat. The best thing we could do is give Gary McKinnon a job. After all, aren't the best security experts usually former thieves?