This sounds a lot like a dictator in the Roman Republic. He was called upon to clean house for a period of time with absolute power when the Republic was threatened from the inside or out. Cincinnatus is one of the good examples I'm aware of.
Theoretically isn't this was the head of state should do in many country's setups? They are the ultimate arbiter of power, and have the power to nominate prime ministers, but don't have real legislative power themselves.
They also have the sword over their head that should they ever use that power, they will be listened to and promptly have their office abolished after. [Or at least that's how I understand the modern British monarchy]
