You have to start here: We are immersed in a freakish and confounding political era. Anything can happen. Surprise is built in. Guy on a lark takes an escalator ride down to a rally and the system is changed forever. “Expect the unexpected.”

That is the context. Within it, consider this: We are misreading Mike Bloomberg’s race for the Democratic presidential nomination. The headline right now is not “Billionaire Tries to Buy Party,” and not “Former Republican Struggles With Stop-and-Frisk History.” The headline is: “He Could...