ROME, Jan. 8 (JTA) — The debate over what Pope Pius XII did — or didn´t — do to save the Jews during the Holocaust is intricate, emotional and one of the key sticking points in otherwise positive relations between the Vatican and the Jewish world. But for Brown University historian David Kertzer, the focus on the wartime pontiff misses the point. "To have the debate reduced to what Pius did or didn´t do between 1939 and 1945 seems almost bizarre," Kertzer told JTA. "I think that if you want to understand the Holocaust, you have to understand how the Jews became demonized," he said. Kertzer is the author of a recent book that seeks to do just that. "The Popes Against the Jews: The Vatican´s Role in the Rise of Modern Anti-Semitism," uses recently declassified documents from the Vatican´s own archives to detail more than a century of anti-Jewish papal policy. "If the Vatican never approved the extermination of the Jews — indeed the Vatican opposed it (albeit quietly)," he writes, "the teachings and actions of the church, including those of the popes themselves, helped make it possible." An expert in 19th-century Italian history, Kertzer was one of the first scholars able to consult the Vatican´s central archives of the Inquisition, which were opened in 1998. He said he wrote his book as a response to the Vatican´s March 1998 document on the Holocaust, called "We Remember: A Reflection on the Shoah." That document said longstanding Christian "anti-Judaism" had nothing to do with the development of the racist "anti-Semitic" ideologies that led to Nazism. He said in an earlier interview that what he shows in the book, based largely on documents found in the Vatican archives, is that "the Vatican was very much involved in the development of modern anti-Semitism." "The Vatican championed a view of the Jews as sinister enemies of the state and of the people, and, well into the 20th century, called for keeping them quarantined from healthy Christian society," he said. Kertzer said that the findings he lays out in his book make the positive changes in Vatican policy in the past few decades all the more dramatic. It was only in 1965, with the promulgation of a declaration by the Second Vatican Council, that the church officially abandoned anti-Jewish dogma. "I don´t see any present danger of slipping back," Kertzer told JTA. "With the Second Vatican Council there was a sharp break with a past in which anti-Semitism was the lifeblood of the church. "The proof of how things have changed is the way that younger Catholics are horrified by the title of my book," he said. "The notion that even after the slaves in the United States were freed Pope Pius IX still confined Jews in Rome in a ghetto, is shocking to them." The Rome Ghetto was only abolished in 1870. Still, he said, "the current stance of the Church is unstable and cannot survive in the long run. You can´t deny history. The Vatican stance is a losing proposition. The sooner they get over it, the better it will be."