Soon after Friday’s terrorist attack killed at least 137 people in Moscow‚ Russian pundits and politicians insinuated that the attackers had links to Ukraine. This came as little surprise. It has become standard for the Kremlin to blame Ukraine for Russia’s internal blunders and accuse it of making common cause with nefarious forces. In October‚ Russia asserted that antisemitic riots at Makhachkala airport in the Dagestan region were inspired by Ukraine. Moscow has also alleged that Kyiv and...