The Rules of the Spy Game Are No Longer Clear

British police confirmed on Wednesday that the former Russian spy Sergei Skripal and his daughter, who are fighting for their lives, had been poisoned by a nerve agent. Police didn't name the substance and knowing what hit the pair isn't the same as understanding who did it. It may be too early to talk of a Russian "declaration of war," as some have done. But the attack raises grave questions.