When Leon Trotsky bragged about being a Communist to a Rabbi, the holy man uttered these famous words, "the Trotskys will make the revolution and the Bronsteins will pay for it." The Rabbi was right -- especially as Trotsky was killed by Stalinist agent Mercador in Mexico in 1939.
Lerner thought because he was a leftist like the others he would be accepted by them, but, as the very patriotic and assimilated Jews of Germany found out, this was not true. The German Jews shaved their beards and were as patriotic and nationalistic as the rest of the Germans, but, when the head of the National Socialist German Worker's party (N.S.D.A.P), Adolf Hitler, took over, it did not matter.
Lerner is the one on the left.
Witness the historical treatment of Wilhelm Frankl: a fighter pilot who died for Germany, he was a holder of the Pour le Merite. He was also a Jew, and Hitler was not about to let the man's sacrifice count for much. Whatever other failings Wilhelm II had (and they were many), his personal anti-semitism apparently had limits. How nice of our homegrown left to be less tolerant than the Kaiser.