There are checks on the judiciary. Unfortunately Congress refuses to exercise them.
I was looking up the judiciary question and I happened to run across this in Wikipedia:
Although the legal orthodoxy is that judges cannot be removed from office except by impeachment by the House of Representatives followed by conviction by the Senate, several legal scholars, including William Rehnquist, Saikrishna Prakash, and Steven D. Smith, have argued that the Good Behavior Clause may, in theory, permit removal by way of a writ of scire facias filed before a federal court, without resort to impeachment.[2]