Former Bush speechwriter Michael Gerson has had his fill of casual comparisons of President Obama and others to Hitler and Nazis. "Nazism is not a useful symbol for everything that makes us angry, from Iraq to abortion. It is a historical movement, unique in the ambitions of its cruelty," Gerson wrote in the Washington Post, warning against such trivialization of Nazi horrors for purposes of argument. People should not be shrinking memories of the Holocaust "to the size of our political agendas and robbing them of their power to shock and teach," he concluded. "The history of those times should be approached with fear and trembling, not mocked with metaphor."