Good old Mccathur, i don't know why Truman got rid of him but i...

Good old Mccathur, i don't know why Truman got rid of him but i think he did.

Well you have to look at the true history rather than your version of the imaginary Brisbane line and the concession of north Oz as this imaginary history was made up and/or pushed by the Labor Minister Eddie Ward most likely for political reasons imo and maybe what he thought should happen or something rather than the actual non-reality of the 'idea'.

A Royal Commission found there was no such documented plans about that fairly tale at all, Ward couldn't even give any evidence or documents to back up what he was saying, apparently Mccarthur mentioned the words "brisbane line' in a news conference which he must have picked up from Aussie media or somewhere i guess or may have been questioned about from the media as real documents for the idea never existed.

" Ward continued to promote the idea during late 1942 and early 1943, and the idea that it was an actual defence strategy gained support after General Douglas MacArthur referred to it during a press conference in March 1943, where he also coined the term "Brisbane Line". Ward initially offered no evidence to support his claims, but later claimed that the relevant records had been removed from the official files. A Royal Commission concluded that no such documents had existed, and the government under Menzies and Fadden had not approved plans of the type alleged by Ward. The controversy contributed to Labor's win in the 1943 federal election, although Ward was assigned to minor portfolios afterward.
https://en.wikipedia.org/wiki/Brisbane_Line

The US would not have wanted a Japanese land invasion of Australia and neither would the UK, to say or suggest the US wanted the japs to invade Oz is a bit out there thinking imo. They were not on the same side.