decades, following the powerful reverberations (concerning the cause of the Nakba) triggered by the publication of books written by those dubbed the "New Historians," the Israeli archives revoked access to much of the explosive material. Archived Israeli documents that reported the expulsion of Palestinians, massacres or rapes perpetrated by Israeli soldiers, along with other events considered embarrassing by the establishment, were reclassified as "top secret." Political and sociological influences on the historical debate Several Israeli sociologists have studied the influence on the historical debate of the political and sociological situations in Israel. Referring to modern sociological schools and commenting historians methodology in the context of the 1948 war and the Palestinian exodus, Uri Ram considers that "contemporary historical revision and debates should be interpreted ... against the backdrop of specific crises in national identities and as an indication of crisis in national identity in the global era." According to him, "the three leading schools writing Israeli history reflect and articulate [the] political-cultural divisions [in the Israeli society]. Traditional mainstream history is national, mostly the labor movement version. On its fringe, a critical school of history emerged in the 1980s associated with post-Zionism (even if some of its protagonists identify as Zionists) [and] finally, in the 1990s efforts have been made to create a counterschool of neo-Zionist history...." "Concept of transfer in Zionism" Discussion of the "idea of transfer" in political Zionism became popular beginning in the 1980s when Israel declassified documents pertaining to the 1948 Arab–Israeli War period and the so-called New Historians began publishing articles and books based on these documents. The Zionist "concept of transfer" was cited by Palestinian authors such as Nur Masalha and Walid Khalidi to support their argument that the Zionist Yishuv followed an expulsion policy, and echoed by a range of Israeli authors including Simons and Flapan. Other Israeli historians, such as Morris, reject the idea that "transfer" thinking led to a political expulsion policy as such, but they explain that the idea of transfer was endorsed in practice by mainstream Zionist leaders, particularly David Ben-Gurion. Critics of the "transfer principle" theory cite addresses by the Zionist leadership that publicly preached co-existence with the Arabs, but in private put forward their own plans, or gave support to plans involving the transfer of Arabs from Palestine. The idea that "transfer ideology" contributed to the exodus was first brought up by several Palestinian authors, and supported