487 Mr R. G. Casey, Minister to the United States, to Mr R. G. Menzies, Prime Minister, and to Sir Frederick Stewart, Minister for External Affairs
Cablegram 407 WASHINGTON, 4 June 1941, 1.05 p.m.
SECRET FOR PRIME MINISTER & MINISTER FOR EXTERNAL AFFAIRS
I had a long talk last night to two highly placed individuals who are close to the President.  I believe all the President's senior advisers are in favour of immediate intervention. Winant  has returned East for a week's visit with the object of impressing the President with the necessity for intervention without further delay.
The President realizes that American public opinion is no longer a bar to any action including warlike action if he tells the public it is necessary in American interests. However, it is for Congress to declare war. President is obliged therefore to avoid the risk of putting any important issue involving the possibility of war up to Congress. This accounts for the fact that the President did not mention Congress in his recent broadcast. Probability is that United States Navy Units will be so disposed and so used as to make an incident a possibility at any time. It is not too much to say that they will 'trail their coat' for an incident.
Germany clearly does not want America in the war. On the other hand I believe it will be necessary for American warships and not merchant ships to be fired upon by German ships or aircraft to produce sufficient of an incident to bring about American belligerency.