UNITED NATIONS, Jul 15 (IPS) – Resolving the Israeli-Palestinian conflict is “key to sustainable peace in the Middle East”, says UN Secretary-General Antonio Guterres, maintaining that the lack of any progress only “furthers radicalization across the region”The Israeli-Palestinian conflict, which dates back to the mid-1940s, is one of the longest military confrontations defying a permanent solution – even as it continues to be on the agenda of the United Nations whose primary mandate is the maintenance of international peace and security.