The main focus in article three is Judicial Branch. And the main focus of the branch is to interpret laws
There is only one Supreme Court and the Court looks at all cases. The judges can be impeached to.
The people who decide if a person has committed treason is the Congress.
The constitution meant laws and different branches coming together to set up a law system for the country of the Untied States for the free but with every action there could punishment or you could be seen to the people.