A senior member of the US Congress has called for a dual-crewed American submarine to be based in Australia as part of an interim measure under the AUKUS agreement.
Republican Rob Wittman also argued Australian shipbuilders and sailors should be sent to the US for months at a time to prepare them for the eventual acquisition of a nuclear-powered submarine fleet.
Mr Wittman was among a bipartisan group of members of the US House of Representatives who sent a letter to President Joe Biden expressing support for the AUKUS deal.
It was prompted by leaked correspondence from two influential senators, warning the provision of nuclear-powered submarines to Australia could push the US submarine industrial base to "breaking point".
Representative Wittman, who was the most senior Republican on the Seapower and Projection Forces Subcommittee in the last congress, said the idea of a direct sale of US submarines was "probably an oversimplification".
But he argued a nuclear-powered boat could be sent to Australia's area of responsibility to help ease a looming capability gap, as the existing Collins class fleet is retired and the new submarines are built.
"I think it would be dual-crewed," he told 7.30.
"I think too, that the command of the submarine would be a dual command, so you'd have an executive officer and a commanding officer that would jointly operate the submarine.
"And this, I believe, is the segue to Australia being able to operate its own submarine."
Another member of Congress who signed the letter to the president, Democrat Joe Courtney, said dual-crewing a US submarine would likely raise other issues.
"Having crews from different navies on a regular basis, operating submarines, strikes me as kind of begging a lot of questions and creating a whole sort of host of other sovereign control questions," he said.
"Having said that, the joint training should happen at full speed."
The Washington director of the Australian Strategic Policy Institute (ASPI), Mark Watson, agreed it would prompt questions about Australian sovereignty.
"If there are crews from the US and Australia on board in a time of crisis, who gets the no-go veto on the use of a particular vessel for a particular task?" he said.
"I think you will definitely see Australians on board US submarines training, for example.
"Whether we get straight to the point of there's a combined and integrated Australian and US crew on a US submarine, that will be interesting to see."
AUKUS supporters insist capacity at US shipyards can be ramped up
Mr Wittman said Australian sailors should complete a full deployment on a Virginia-class submarine, while shipbuilders should travel to the US to help construct one of the boats.
"So to show up here when they start cutting the first piece of steel to the time that that boat is put in the water," he said.
"Because it's only that experience that's going to fully inform Australian shipbuilders as to the scope of what they're doing and to understand how these boats are built and how they're put together."
US shipyards are under pressure as the Navy tries to catch up on its target of increasing its nuclear-powered attack fleet from 50 boats to at least 66.
In their letter to Joe Biden, senators Jack Reed and James Inhofe argued what had been touted as a "do no harm" opportunity might instead become a "zero-sum game" for scarce resources.
But representatives Courtney and Wittman, both of whom represent districts with close ties to the shipbuilding sector, argued capacity could be increased.
"You know, honestly, if AUKUS really works the way it should, there should be contribution to this program from the UK and Australia," Mr Courtney said.
"And I think that shows that, you know, that's a force multiplier that can really help take on the larger demand."
US debate opens up 'political risk', analyst says
Nearly 18 months after AUKUS was first announced, the Australian government will soon detail which nuclear-powered submarines it plans on acquiring and how long it will take.
The Australia chair at the Centre for Strategic and International Studies, Charles Edel, said the agreement was always going to be complex.
"In diplomacy, oftentimes the way that this happens is you figure out what the agreement is, and then you announce it. You do all the hard work beforehand," he said.
"That's not how this happened, right. We announced it and then we said, 'Oh, and now we have to figure out how we're going to go about it'.
"So that's why the first announcement was, 'We're going to go mum for the next 18 months, because we have to figure out how we're going to do this, on what timeline, with which companies, in which countries, on what type of delivery timetable.'"
Defence Minister Richard Marles insists AUKUS remains on track, with an announcement due by the end of March.
However, ASPI's Mark Watson said the recent debate in the US had opened up a layer of "political risk" that might not have been anticipated.
"There is still very strong bipartisan support for AUKUS and the submarines program," he said.
"The problem will come if that morphs into an 'AUKUS yes, but maybe not right now, because we have our own problems with our own submarine fleet.'"
Congressman accuses China of trying to 'bully' Australia through AUKUS criticism
Beijing has repeatedly criticised AUKUS, accusing the three member countries of targeting China and describing Australia's pursuit of nuclear-powered submarines as a waste of money.
But backers of the agreement in Washington argue it is necessary for security in the Indo-Pacific.
"They [China] don't have a right to tell Australia what they can and can't do, they just don't," said representative Adam Smith, the ranking member of the House Armed Services Committee who also put his name to the letter to President Biden.
"I'm sure China would like to be able to bully Australia more effectively.
"But I completely applaud the Australian government and the Australian people for saying, 'Nah, we're not going to go for that. We're going to have the partnerships that we want to have.'"
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