THE last phase of the debate on the application of the trusteeship system to the former Japanese-mandated islands has now opened. The American position in regard to the control of the islands, certain of which are now included in our chain of military bases, was described by President Truman in a statement on November 6 and set forth in detail in a published proposal which later will be submitted to the Security Council. This proposal is in the nature of a compromise between the principles of collective and national security.