The challenge is to address legitimate Israeli security concerns while respecting Palestinian sovereignty. The key lies in an international presence that can only be withdrawn by the agreement of both sides.  Israeli withdrawal should be phased over 36 months while the international force is gradually introduced into the area.  At the end of this period, a small Israeli presence in fixed locations would remain in the Jordan Valley under the authority of the international force for another 36 months.  This period could be reduced in the event of favorable regional developments that diminish the threats to Israel.  On early-warning stations, Israel should maintain three facilities on the West Bank with a Palestinian liaison presence; the stations would be subject to review after three years, with any change in status to be mutually agreed.  For defining what would constitute an “emergency,” formulations should be used that refer to “an imminent and demonstrable threat to Israel’s national security that requires Israel to declare a national state of emergency.”  The international forces would need to be notified of any such determination.  On airspace, the state of Palestine will have sovereignty over its airspace but the two sides should work out special arrangements for Israel training and operational needs.  While Israel wants Palestine to be defined as a “demilitarized state” and Palestine wants to be defined as “a state of limited arms,” both should think in terms of a “non-militarized state.”  This would be consistent with the fact that, as well as a strong Palestinian security force, Palestine will have an international force for border security and deterrence purposes.  Whatever the terminology, both sides will need to work out specific understandings on the parameters of the Palestinian security forces.