The rule of law is a crucial dividing line between free societies and tin-pot dictatorships. One central element of that is that our constitutions and legislatures write the rules down, and the text of written rules is binding on the government and the citizen alike. Another is that we have the same law for everyone. A person who is wealthy, prominent, or politically important is subject to the same rules as someone who is poor, obscure, or uncontroversial. The combination of written rules and their equal application makes up a system of equal justice and limited government.

Perfectly equal justice will …