Roosevelt had returned from Hyde Park troubled that Felix Frankfurter and Bohr had somehow breached Manhattan Project security, Bush and perhaps Conant had talked to Bohr and the two administrators had submitted to Stimson at his request a more detailed proposal incorporating Bohr's ideas. In doing so they had explicitly recommended that the United States sacrifice some portion of its national sovereignty in exchange for effective international control, understanding as they did so that they would have to answer vigorous opposition: