King John has unlimited power. All governmental functions are exercised by him and his appointed advisers. The King makes legislative instruments and has the ultimate judicial power.

There has been a recent fundamental change. King John now has to consult the King’s Council before exercising governmental functions. This protects certain individual rights.

King John is elected. He must represent the interests of his people and be accountable and responsible for any decisions he make. If he chooses to ignore the wishes of his people he risks not being re-elected. 

King John signed a peace treaty after a dispute he had with the Barons. This allows the Barons to force King John to do exactly what they want. King John has very little power.