The revelation that "retired" soldiers are operating in Libya with the blessing of Nato countries, under the guise of working for private security companies, has sparked new debate about the use of ground forces there.

This raises two separate issues – one legal, the other political. Politically, ground forces are unacceptable but the military have been seeking some assistance from the ground and private companies are one way of providing it.

There is also a popular belief that Security Council resolution 1973, which provides legal cover for the Nato operation, excludes the use of ground forces too. From a cursory reading, you might easily get that impression. But what it actually rules out is "a foreign occupation force of any form on any part of Libyan territory".

Exactly what this means hinges on the legal definition of an "occupation force" and the Hague Conventions of 1907 are pretty clear about that. Article 42 says: "Territory is considered occupied when it is actually placed under the authority of the hostile army."

So, legally speaking, the resolution would probably allow Nato to send in an entire army if it wished, so long as it did not assume authority over any Libyan territory.

Posted by Brian Whitaker, 2 June 2011.