A confederate system of government is one where regional, or state, governments hold most of the power and the central government is weaker. The central government holds only the amount of power that the smaller political units allow it to exercise. This type of government is much less common than federal or unitary systems.
The main advantages of the confederate system of government is that it keeps the power of the central government in check. Citizens of the various states within the confederation need not fear that a strong central government is going to take actions that harm their region. The central government only involves itself in matters that involve cooperation among the states.
This system also has certain disadvantages that make it difficult to function successfully over time. A weak central government has great difficulty enacting and collecting taxes, which makes it hard for the central authorities to enforce laws. The central government is often unable to settle disagreements between the various states as well.
The main areas of activity for a central government in a confederate system are providing for the common defense and dealing with trade issues among the member states. One well-known historical example of a confederation is the Confederate States of America.