The judicial branch of the government is responsible for evaluating the constitutionality of the laws passed by Congress.
While arguably the most important branch of the government, the judicial branch is the one over which we the people have the least control. While the Supreme Court is mandated by the U.S. Constitution, congress has the responsibility of determining the shape and structure of the federal judiciary.
The Supreme Court is currently made up of 9 judges. It has been made of as few as 6 justices in the past. We elect zero of them. The sitting President nominates them as a vacancy appears and the senate approves the choice. They serve until they die or choose to retire. Each appointed judge will far outlast the president who appointed him or her, by a long shot. They begin their year the first Monday in October and continue until the end of summer. Fewer than 1% of the cases appealed to the Supreme Court are accepted to be heard.
In addition to the Supreme Court, the federal judiciary is made up of 94 US District Courts (trial) and twelve US Circuit Courts (of appeal) The federal courts can only make rulings on issues that involve breaking laws laid down by the Constitution. These judges aren’t necessarily concerned about behavior being right or wrong, only whether or not said behavior is allowed by the Constitution as they interpret it. They are the voice of the Constitution.
Interpreting a 200 year old document is an awesome responsibility. Is the Constitution a divinely inspired piece that should be interpreted as it was originally written? Or is it a living document that should evolve with the times?
As you can imagine, a lot of political controversy stems from this interpretation. Here, I invite you to try it for yourself!