When, if ever is the sovereign power justified in limiting the freedom of the people and persons?

"Government exists to protect us from each other, not from ourselves" (Ronald Reagan). Government has the right to restrict freedom for national security when necessary (i.e. martial law), but not for the purpose of doing what it thinks is best for us (i.e. socialism). Of course, this flies in the face of the anarchists' desire to run naked through the streets with a lit stick of dynamite without government restriction.