King John of England, who 800 years ago this week was forced at Runnymede to affix his Great Seal to Magna Carta—which at least in theory subordinated his power to law—might have envied President Obama. Sure, Obama pays lip service to idea that the executive is subject to law, Sheldon Richman writes. But what happens when he acts like an autocrat? Nothing. Obama has been at war with the Islamic State for a year, and his administration won't even do us the courtesy of spelling out his legal authority in detail.