So what should we seek in order to avoid or at least reliably reduce the availability of such arbitrary exercise of power? The commonest forms of answer – limiting, constraining, curbing – cast the role of the rule of law as defensive and negative, often exclusively so. These terms typically miss the positive, often constitutive, and anyway indispensable role of power in social affairs and in what we should hope for if the rule of law is to attain its proper ends. I recall the term ‘tempering’ as long used, but largely forgotten, to express the ambitions of those pursuing values then and long since associated with the rule of law. In part a description, in part metaphor, the idea of ‘tempering’ gives more food to thought and possibility than the defensive, diminishing terms in common use. I demonstrate that in its various uses – personal, institutional, metallurgical – the term evokes a salutary combination of balance, thoughtfulness, moderation, and strength appropriate to the rule of law ideal.