From Hayek:
The Rule of Law was consciously evolved only during the liberal age and is one if its greatest achievements, not only as a safeguard but as the legal embodiment of freedom. As Immanuel Kant put it (and Voltaire expressed it before him in very much the same terms), "Man is free if he needs to obey no person but solely the laws." As a vague ideal it has, however, existed at least since Roman times, and during the last few centuries it as never been so seriously threatened as it is today. The idea that there is no limit to the powers of the legislator is in part a result of popular sovereignty and democratic government. It has been strengthened by the belief that, so long as all actions of the state are duly authorized by legislation, the Rule of Law will be preserved. But this is completely to misconceive the meaning of the Rule of Law. This rule has little to do with the question whether all action of government are legal in the juridical sense. They may well be and yet not conform to the Rule of Law. The fact that someone has full legal authority to act in the way he does gives no answer to the question whether the law gives him power to act arbitrarily of whether the law prescribes unequivocally how he has to act. It may well be that Hitler has obtained his unlimited powers in a strictly constitutional manner and that whatever he does is therefore legal in the juridical sense. But who would suggest for that reason that the Rule of Law still prevails in Germany?
To say that in a planned society the Rule of Law cannot hold is, therefore, not to say that the actions of the government will not be legal or that such a society will necessarily be lawless. It means only that the use of the government's coercive powers will no longer be limited and determined by pre-established rules. The law can, and to make a central direction of economic possible must, legalize to what all intents and purposes remains arbitrary action. If the law says that such a board or authority may do what it pleases, anything that board or authority does is legal - but its actions are certainly not subject to the Rule of Law. By giving the government unlimited powers, the most arbitrary rule can be made legal; and in this way a democracy may set up the most complete despotism imaginable.
Or the Clintonista saying something about Executive Orders - "It's great! No Congress or courts to worry about!".