Howard and Downer accurately described what the ANZUS Treaty says - it only takes effect if there is an attack on the metropolitan territory or in the Pacific on one of the partners.
It doesn’t apply in any other circumstance.
That is why the only time it has been invoked was after September 11 because in that case there was an attack on the metropolitan territory of the United States.
But that does not mean Australia would not to the aid of the US as an ally in the case of war with China.
ANZUS did not apply in Vietnam, or in the Gulf War of 1991, or in the Iraq War of 2003. Australia still provided support to the US as an ally in all those cases.
ANZUS does not define the entire alliance between Australia and the US - it exists to deal with one specific circumstance - an attack on the partners.
Nonsense.
It was latter weaseling due to ChiCom influence, attempts to placate the communist regime.
Have you read Silent Invasion yet?
[But that does not mean Australia would not to the aid of the US as an ally in the case of war with China.]