As I type this, I'm waiting for President Obama's already long-delayed late-night address, in which he is expected to announce that Osama bin Laden has been assassinated. As with the execution of Saddam Hussein, it was morally wrong, and it is unlikely to resolve anything.
On the first point, everyone deserves a fair trial, and no-one deserves to be executed. That applies to monsters like Saddam Hussein, and it certainly applies to mass-murderers like Osama bin Laden. Killing people for their crimes is wrong. Killing them without a fair trial is worse. It is not justice; it is murder. Those taking satisfaction in it, are vengeful sadists, with the ethics of kitten-strangling psychopaths who kill for pleasure.
(Phil Goff is apparently one of those psychopaths. I will not support anyone who supports extrajudicial execution, and such a person is unfit to hold a seat in the New Zealand Parliament, let alone be its Prime Minister).
Secondly, while Americans are already cheering the death, it doesn't actually solve anything. This is the real world, not a fantasy novel. The world is not suddenly set to rights because the Dark Lord is dead. To point out the obvious, the Taliban are fighting their own war, not bin Laden's; they are not going to lay down their arms because an old man is dead. Likewise, al Qaeda as an organisation isn't going to magically disappear with bin Laden's death, and the long war he has started is not going to end - not as long as the US keeps murdering innocent civilians in Afghanistan and Pakistan. It will be justice, not murder, which ends that terrorist campaign.
The only positive aspect of this is that it now gives the US an excuse to declare victory in Afghanistan and go home, and cease providing more recruits for terrorist networks with their presence and impunity. The sooner they do so, the better.
