President Barack Obama said just before the recent Ferguson, Missouri, riots, "First and foremost, we are a nation built on the rule of law." Most Americans have little or no inkling of what "rule of law" means. Many think it means obedience to whatever laws legislatures enact. That's a vision that has led to human tragedy down through the ages. Historically, it sanctioned the divine right of kings, whereby a monarch was subject to no earthly authority, deriving his right to rule directly from the will of God. More recently, it's a vision that included the Nuremberg laws, which led to the genocide of European Jews, and the brutal laws of the regimes of Josef Stalin and Mao Zedong, which led to tens of millions of murders.