The phrase “Weimar Russia” first appeared about 13 years ago, at the height of the confrontation between then President Boris Yeltsin and the Supreme Soviet that ended when Yeltsin’s tanks shelled the parliament. The meaning was clear to all: Weimar Russia, like Weimar Germany, signified a weak republic attacked from within by nationalists yearning to restore authoritarian ways.In the late 1990’s and the early years of this decade, the problems that incited fears of a dysfunctional state seemed to fade. But over the past 18 months, the specter of Weimar has once again begun to haunt Russia.If taken to extremes,...