[Consort]

Congress can clip their robes. They don't want to push things beyond what a majority of congress will tolerate.

What can Congress do to them?

[DPB101]

Add or subtract the number of justices. Limit appellate jurisdiction. Maybe some other things. Turn off the heat in the winter and A/C in the summer?

U.S. Constitution
Article III
Section 2

In all cases affecting ambassadors, other public ministers and consuls, and those in which a state shall be party, the Supreme Court shall have original jurisdiction. In all the other cases before mentioned, the Supreme Court shall have appellate jurisdiction, both as to law and fact, with such exceptions, and under such regulations as the Congress shall make.