Ah, yes... the US side - which has specifically passed laws approving and supporting AUKUS and committing the US to providing those 3 Virginia class SSNs.
Well yeah, but the agreement still includes provisions for the US to back out of the transfer of submarines if it feels the need.
And despite Marles' and Mead's faith, we won't know for sure until the boats show up and there's an official handover which is still a looong way off.
And absolutely the US side has passed laws approving and supporting AUKUS, why wouldn't they? They get a sub base in WA and possibly NSW, nuclear armed B-52s sitting on the ramp at Tindal ready to go at a moments notice, air refuelling facilities and aircraft at Darwin, a permanent Marine presence in NT and a shit-ton of equipment pre-positioning in VIC.
All of it under the control of US troops.
Not to mention the billions in investment that Australian taxpayers are providing to boost US and UK submarine building instead of boosting their own, and all of it without even a parliamentary debate, all decided by a small group of people, behind closed doors.
The fact is, the US military will be so embedded in Australia's 'interchangeable' defence force by the time the transfer comes around and Australian politicians so compromised by a decade of lobbying and kickbacks that the US will be able to basically write it's own cheques.
So no, there's no way the US would walk away from AUKUS. They may finesse the handing over of submarines though, that remains to be seen.