The United States, nevertheless intentionally avoided overt direct intervention. In February 1954, following the French occupation of Điện Biên Phủ, Democratic senator Michael Mansfield asked the United States Defense Secretary, Charles Erwin Wilson, whether the United States would send naval or air units if the French were subjected to greater pressure there, but Wilson replied that "for the moment there is no justification for raising United States aid above its present level". On 31 March, following the fall of "Beatrice", "Gabrielle", and "Anne-Marie", a panel of U.S. Senators and Representatives questioned the US Chairman of the Joint Chiefs of Staff, Admiral Arthur W. Radford, about the possibility of US involvement. Radford concluded it was too late for the U.S. Air Force to save the French garrison. A proposal for direct intervention was unanimously voted down by the committee three days later, which "concluded that intervention was a positive act of war".