WASHINGTON, March 1--Secretary of State Dean Rusk told a press conference that the United States is the March 15 Geneva Disarmament with "a measure of hope on basis of realistic proposals."

The trail ahead of us in the arms race and dangerous," Rusk said, it necessary to seek steps "to this spiral down." Therefore, the will use this conference to try to disarmament "out of an exchange of he said.

Abandoning his usual brisk manner, continued, "We have to hope... have to hope, we have to try to make basis for hope. The steps we may at this conference will make a big to the human race."

Rusk spoke in the plush conference of the new State Department members of the Young Democratic of Harvard and Radcliffe received a briefing on American policy on and Latin America. An official them that the Alliance for Progress "necessarily an instrument of U.S. policy," which justified "table pleas" for a tough line against at the recent Punta. del Este . The alliance is not "just a giving away of money," he noted. The official repeated the formal United position that President Kennedy responsibility for any American in the April invasion of . However, he referred the group Theodore Draper's article in the New and Encounter for accurate ing of the invasion.

While the United States has definitely out another invasion, the official the State Department is now hoping the collapse of the Cuban economy an internal revolt against Castro.