The US has 50 state governments that work with the federal government. One of the reasons for this cooperation is the large public works projects that benefit all states. Like the federal government, state governments are divided into three branches: the executive, legislative, and judicial. The state executive branch is headed by the governor. The executive branch implements (executes) state laws. Officials in the legislative branch create state laws, and members of the judicial branch define and interpret those laws. The judicial branch of the state government not only comprises the state's supreme court, but also the entire state court system.

Some of the main powers of state governments are:

setting state election law
creating, executing, and interpreting state law
regulating local government.
Some of the main responsibilities of state governments include:

running state police and corrections
administering the state education system
maintaining state properties and facilities.
State governments must abide by their state's constitution. State constitutions are regularly amended. The powers and responsibilities of the state government apply only within their own borders, not within those of other states, and do not take precedence over federal law.