Ironically Marbury was about Congress gutting the courts. Jefferson's Congress canceled 18 federal courts, leaving 18 judges (appointed by Adams at the end of his term, and who had not yet been seated) with no court to sit in! The case was a suit to force Jefferson's Secretary of State (Madison!) to give those new judges their commission. Marbury is a fairly complex case.

Anyways, Adams' 18 judges were not sat. This could happen again: just close out a bunch of judges' courts -- they'll still be judges for life, but judges without a court.