John McCain has made it clear this week he doesn't understand what's happening on Wall Street any better than Barack Obama does. But on Thursday, he took his populist riffing up a notch and found his scapegoat for financial panic -- Christopher Cox, the chairman of the Securities and Exchange Commission.

To give readers a flavor of Mr. McCain untethered, we'll quote at length: "Mismanagement and greed became the operating standard while regulators were asleep at the switch. The primary regulator of Wall Street, the Securities...