While the Supreme Court Justices are nominated by the President of the United States and approved by a majority vote of the Senate, the Justices serve until they either retire, die or are impeached.
The Constitution was vague when interpreting the term for Supreme Court Justices. While the Judicial branch is the third branch of our government, it's power has grown disproportionate over the Legislative and Executive branches. This is in part due to the lifetime appointment of Justices, which today is decided primarily by partisan politics. Justices now make decisions based on political ideology instead of constitutionality.
We need to change the lifetime appointment of Supreme Court Justices to a one term limit of ten years.