The use of deadly force against Bin Laden is unlikely to be challenged in an American court. But the White House’s account of the operation suggests it is mindful of legal issues. The al-Qaeda leader is said to have “resisted during the raid” – although it is not clear how he did so, as he is also said to have been unarmed.
Assassinations are banned under both US and international law. Extrajudicial killings are only allowed in an armed conflict.
According to British law professor Philippe Sands QC, of University College London, much will turn on what Pakistan knew and authorised, what the US objectives were, and what happened when they confronted Bin Laden.
Until the facts are established, it is unclear whether the raid and its consequences were legal or not, Mr Sands adds.
The US can certainly argue that it was entitled to take action to protect its citizens against a deadly enemy.
“Even if the use of deadly force was unlawful, international law recognises that there are exceptional circumstances where necessity precludes wrongfulness, and this will be said to be one of those case,” Mr Sands told the BBC.