The Judical branch's main responsibility is to approve laws, and resolve certain conflicts. It also gives congress the power to create lower courts to meet the nations needs
This is also the branch that deals with federal issues, or people accused of federal crimes, and the justices will serve for life until they die or retire. There are only nine of these justices.
The Supreme Court also does something else that's extremely important, the Supreme Court decides if a law is unconstitutional or if it would cause one of the other branches to be unconstitutional.