A basic requirement of a functioning and civilised society is the ability to rely on the police and the courts to uphold the law and to resolve disputes fairly.
When those functions are usurped by groups outside the state's control, we get anarchy, mob rule, and corruption.
This was the case in Libya, and it resulted, among other things, in the assassination of US Ambassador Chris Stevens, and the destruction of Sufi sites.
Finally the government has started clamping down on illegal militias, but only after the people acted first; the state reacted rather than taking the initiative.
The fear now is that these groups will be harder to eliminate as they have gone underground, along with their weapons.
Nevertheless, the government's only option is to keep up the pressure and ensure that it and it alone retains responsibility for policing and justice.
The government was chosen by the people, and the recent demonstrations by ordinary Libyans reaffirm that the government has the consent of the people.