Richard Nixon's "enemies list" appalled the country for the simple reason that presidents hold a unique trust. Unlike senators or congressmen, presidents alone represent all Americans. Their powers—to jail, to fine, to bankrupt—are also so vast as to require restraint. Any president who targets a private citizen for his politics is de facto engaged in government intimidation and threats. This is why presidents since Nixon have carefully avoided the practice. Save Mr. Obama, who acknowledges no rules.