Wisconsin circuit courts
In addition, the courts are constrained from taking action that will encroach on the powers of the legislative or executive branches. Under the separation of powers doctrine, no branch of government may exercise a power of government assigned exclusively to another branch. The purpose of separating powers among the branches of government is to avoid concentration of governmental power in the hands of a new and to give the various branches the ability to check actions by the other branches.
Article Three of the United States Constitution
The Supreme Court is the only federal court that is explicitly established by the Constitution. During the Constitutional Convention, a proposal was made for the Supreme Court to be the only federal court, having both original jurisdiction and appellate jurisdiction. This proposal was rejected in favor of the provision that exists today. Under this provision, the Congress may create inferior (i.e., lower) courts under both Article III, Section 1, and Article I, Section 8. The Article III courts, which are also known as "constitutional courts", were first created by the Judiciary Act of 1789, and are the only courts with judicial power. Article I courts, which are also known as "legislative courts", consist of regulatory agencies, such as the United States Tax Court.