The European version of the Mandate of Heaven is really an interesting creature. While there is not direct means of withdrawing the mandate in the event of a tyrannical ruler, the assumption is that the Church would step in at the appropriate time and wield Divine Justice.
It is really a catch 22. The Divine Right of Kings was mostly codified by St. Thomas Aquinas and was used in an effort to reign in the would be Holy Roman Emperors. It seems the Church had to chain themselves to the lion in order to control it.