The Court that is established by the Constitution and so cannot be abolished by Congressional law is the Supreme Court
The U.S. Constitution:
This means that Congress can abolish every other federal court apart from the Supreme Court because they created it but they cannot abolish the Supreme Court unless an amendment to the Constitution was made.
In conclusion, the answer is the Supreme Court.
Find out more about the creation of the Supreme Court at https://brainly.com/question/932365.