BEIRUT, Lebanon , June 30 (UPI) -- The United States, which brokered Lebanon and Israel's first direct negotiations and framework agreement, is Lebanon's only guarantor for securing a full Israeli withdrawal from its territory and bringing an end to the decades-long conflict between the two countries, official and diplomatic sources said. The preliminary agreement, signed last Friday in Washington, marked the beginning of a long and difficult process whose outcome would depend on U.S. President