It has one of its most important roles there.
Breach of contract is equivalent to theft.
We don't allow the victim of a crime to determine the jail sentence or even restitution. They are bound by law to accept the due process proceedings of the governemnt in the dispute resolution. One of the few things libertarians think the government DOES exist for, is to resolve disputes in which a persons rights have been violated. Only the government can decide the penalty for breaking the law. This distingusihes libertarians from anarchists.