44 Curtin to Churchill
Cablegram 420  CANBERRA, 11 September 1942
IMMEDIATE MOST SECRET
Reference your No. 594 , it is learnt with considerable surprise that there has been a change in the views notified in No.
362 of 6th April , which contemplated a strategic offensive action in the Pacific by the transfer of forces from the Indian Ocean to the Pacific when certain essential Conditions had been fulfilled.
2. It would now appear that instead of the Eastern Fleet being built up to the strength necessary for this purpose, it is being disposed in theatres other than the Indian and Pacific Oceans.
3. If a superior naval force is not to be concentrated to inflict a decisive defeat on Japan and relieve Australia of the threat of invasion, there is no alternative but to press for the land and air strength necessary for the local defence of the Commonwealth, the case being parallel to that referred to by you in paragraph 3 of No. 594, relative to the defence of India and other territories in the Indian Ocean. I have addressed to the President  and yourself  my representations on air requirements. In a separate communication the need for additional land forces is dealt with.
4. The following will be recalled from the review of the United
Kingdom Chiefs of Staff on Australian Defence, which was transmitted in Mr. Bruce's cablegram No. 55 of 3rd April :-
'A movement of the United States main fleet into Eastern Australian waters provides at present the only sure means of protecting the Eastern Australia and New Zealand, but the United States Fleet cannot undertake to remain in Australian waters indefinitely. The Allied aim should therefore be to build up the land, air and local Naval Forces in Australia and New Zealand to a point where they can stand without the immediate support of the United States Fleet, and can ensure that they will not be defeated before the United States Fleet is able to return to sever the enemy's communications with her invading forces.'
Whilst the security of the line of communication to the United States is of vital importance, it is hoped that it is clear to those responsible for grand strategy that the interruption of this line is neither an essential preliminary nor even a necessarily desirable condition to a Japanese assault on the mainland of Australia, if the local land and air defence strength is to remain at its present figure.
5. If Japan succeeds in capturing Port Moresby, the way is open to a direct attack on the mainland under cover of land-based aircraft, which may well defy all naval attempts to interrupt their line of communication and dislodge them.
6. In view of the possibility that an attack may be launched against Western Australia by Japanese forces from the Netherlands East Indies, I would also be glad to know the views of the United Kingdom Chiefs of Staff on the contemplated strength of the Eastern Fleet as a deterrent to such an attack, and the possibility of its use should such an attack eventuate, having regard to its other commitments in the Indian Ocean.