I forget, now that I'm down here writing about it, just who said, above:

Right now, the Judicial branch of our US government has far more power than either of the other two branches, in part because of that decision/precedent and in part because of the lifetime appointment of Federal justices. (Not sure how far down that extends, but it's not just for the SCOTUS.)

All "Article III judges" are appointed "for life, during good behavior". (See below)   

Article III judges are US District Court judges (the trial-level judges in the federal system), judges of the various courts of appeals, and the Supreme Court. There has been some push to make judges of the various bankruptcy courts Article III judges, but as far as I know that has gone nowhere. The argument for bankruptcy judges to be Article III judges is essentially that bankruptcy jurisdiction used to be part of the realm of US District Court judges, before that jurisdiction was split off into a separate court.

"Good behavior" essentially, in the real world, means that you can't get convicted of a felony and still keep the appointment. That's never happened, as far as I know.

Dave Oesterreich