By John Blake, CNN Russian President Vladimir Putin often evokes the Soviet Union's epic defeat of Nazi Germany during World War II to justify his country's invasion of Ukraine. Yet Putin is committing some of the same blunders that doomed Germany's 1941 invasion of the USSR -- while using "Hitler-like tricks and tactics " to justify his brutality, military historians and scholars say. This is the savage irony behind Putin's decision to invade Ukraine that's become clear as the war enters its second month: the Russian leader, who portrays himself as a student of history, is floundering because he hasn't...