Russia just took another bite out of Ukraine by trucking “peacekeepers” into the eastern provinces—a clear act of aggression. (See Main Stories, p. 4.) But to hear Vladimir Putin tell it, it’s always the Russians who are the victim, forever betrayed by the West. The Russian president’s immediate pretext for his escalation was a fictional Ukrainian “genocide” of Russian speakers. The underlying reason, though, was his fury at what he sees as NATO’s breach of promise. Putin purports to believe that German reunification in 1990 came with the understanding that East Germany was the only ex–Warsaw Pact member that would join NATO. The Baltic states’ accession in 2004, he says, was in bad faith, and Ukraine’s would be utter treachery. In the real world, there was no such deal, as…