It was a turning point in 21st-century history. Or it was an act of cynical political calculation. Heck, there’s no law that says it can’t be both.British Foreign Secretary Ed Miliband took the floor in the House of Commons on Sept. 8 to deliver one of the most remarkable speeches heard there in many years. It wasn’t a magnetic performance; nobody’s likely to compare Miliband to Winston Churchill or Barack Obama as an orator. He’s a policy-driven intellectual with degrees from Oxford and the London School of Economics, long identified with the “soft left” of the British Labour Party. (His...