Friday, a group of ISIS extremists claimed credit for the attack on a Moscow theater that killed at least 133 people and left the building a smoldering ruin. But Russian President Vladimir Putin, in his public comments today, didn’t mention ISIS-K: instead, he placed the blame on Ukraine. As The New York Times headline after Putin’s remarks laid out: “In First Remarks on Attack, Putin Tries to Link Assailants to Ukraine.” The article’s lede says it all: “President Vladimir V. Putin of Russia laid the groundwork on Saturday for blaming Ukraine for the Moscow concert hall attack. And in making h…