Plan Dalet was the Zionist military plan to occupy contiguous areas of Palestine, and is to all intents and purposes, the official authorization by the Zionist leadership of the Nakba . According to Israeli historian Ilan Pappe, it was formulated by a group, chaired by David Ben-Gurion, that he calls, The "Consultancy" , and was sent out to Zionist field commanders on March 10, 1948.1
It authorized the use of various destructive measures in case of Arab resistance, including blowing up of villages, setting fire to villages, and mining the debris left after the destruction. In the case of armed resistance, Plan Dalet specifies that the resistance should be "wiped out," and the population removed "beyond the borders of the state." Pappe points out that Plan Dalet had evolved when it was clear that attempted occupation would always provoke some kind of resistance, so its offensive measures were, for all practical purposes, universally applicable.2
Plan Dalet wasn't implemented immediately, but was postponed until the British evacuation of Palestine had reached the point where British forces could no longer threaten Hagana. This point was reached on or about March 31, 1948, and Plan Dalet was then carried out in a series of operations between April 1 and May 15.3
1 Ilan Pappe, The Ethnic Cleansing of Palestine , (Oxford: OneWorld, Paperback, 2010), xii
2 Pappe, 82
3 Rosemarie M. Esber, Under the Cover of War , (Alexandria, VA: Arabicus Books & Media, 2008), 179