Your M.179.  His Majesty's Government in the Commonwealth of Australia appreciates that it would be difficult for constitutional reasons to secure guarantee of armed support from United States Government. We also agree that to attempt to gain acceptance from United States Government of an assumption on part of British Commonwealth of United States armed support in contingencies mentioned might cause embarrassment.
We cannot, however, accept apparent conclusion drawn in your telegram that question of United States action in event of violent Japanese reaction should therefore not be raised at all in Washington at this stage. Having regard to our consistent attitude on this matter over the past year, and from point of view of highest interests of our national security, we would frankly find it impossible to justify embarking at this critical point on a course of action which might lead us into war with Japan unless some satisfactory understanding had first been reached with United States. We could not regard expectation set out in paragraph 4 of your telegram under reference, however well-founded, as sufficiently meeting this condition.
His Majesty's Government in the Commonwealth of Australia earnestly hopes that you will realise its standpoint on this matter. In para. 4 (3) of your telegram M.172  you implied that every effort should be made to obtain from United States Government clearest possible indication that we could count without reservation on their active armed support. With this in mind we emphasized in our reply telegram No. 467  necessity for utmost frankness in exchanges with United States Government. We are still firmly convinced of this necessity. It seems to us entirely feasible that in notifying readiness of British Commonwealth to concert with United States in proposed economic action, British Ambassador should intimate that we clearly realize possible consequences of action, both for ourselves and for Netherlands, and that we assume that United States Government also realizes them. In discussion which will arise on this basis, indication of United States attitude will certainly appear. The nature of this in all probability will constitute satisfactory understanding which we feel to be essential. We consider it vital, however, that question should be raised in one form or another.