As the US reviews the AUKUS submarine deal, some have called for Australia to do the same, while others have suggested the partnership should be left behind.
The review has also sparked discussions about the agreement, which country has the most at stake, and what would happen if the deal was scrapped.
Here's what you need to know.
What is AUKUS?
AUKUS is a security partnership between Australia, the US, and the UK. It was announced in 2021 when Scott Morrison was prime minister of Australia, Joe Biden was president of the US, and Boris Johnson was prime minister of the UK.
Under the $368 billion agreement, Australia will acquire three Virginia-class submarines from the US in the early 2030s before a new fleet of boats is built for delivery from the 2040s.
The deal lasts until 2075, and countries can cancel the contract with one year's notice.
Why is the US reviewing AUKUS — and is it significant?
The Trump administration has confirmed that a review into AUKUS will be conducted by Elbridge Colby, the defence under secretary for policy, to ensure the program meets its "America First" criteria.
On Thursday morning, Defence Minister Richard Marles said the review was "not a surprise", and said it was "perfectly natural" for an incoming government to do so.
David Andrews, senior policy advisor at the ANU National Security College, said it's not abnormal for governments to conduct reviews into this type of agreement.
"For a project of this size and with new governments and new parliaments, it would make sense that for their ... understanding and full knowledge of what's going on in the project, doing their job as parliamentarians or as members of Congress to review and hold to account decision makers, that's a natural part of the democratic process," he said.
The US is not the first to review AUKUS, with the UK also conducting an assessment last year, and reaffirming its commitment to the agreement.
But Andrews said there have also been questions as to whether the US review has been motivated by US desire for allies, including Australia, to increase defence spending.
"So the most generous version would be to say [the US] want to understand what's going on ... so that they can best plan and account for that to ensure it is delivered effectively," he said.
"But I can understand why people would have quite reasonable concern or scepticism about the bona fides of the review ... there does seem to be a few additional factors going on that we can't rule out."
Arthur Sinodinos, former Liberal minister and now partner and chair of Australia practice at the Asia Group, said a review was "always on the cards" under a new US administration, and said he does not believe the pact is in jeopardy.
"This is an opportunity for the new administration to own the AUKUS agreement and to put their stamp on it, so we should view it in that way," he said.
"And it's an opportunity for us to remind the Americans, not so much that we need them, but that they need us when it comes to the essentials of their security in the Indo-Pacific."
Should Australia 'abandon ship'?
In a media release on Thursday morning, The Greens said it was time Australia "abandoned ship" and suggested the US would not supply Australia with the second-hand submarines in the early 2030s as agreed under the deal.
Greens spokesperson for defence and foreign affairs David Shoebridge said Trump would "put US interests first and allies last".
NSW Greens senator David Shoebridge has suggested Australia should "abandon ship" on AUKUS. Source: AAP / Mick Tsikas
"It’s time for Parliament to launch a full inquiry into this dud deal, and allow critics of AUKUS a seat at the table, not just a nodding bunch of Labor and Coalition members."
But opposition defence spokesperson Angus Taylor expressed concern about the review and the possibility of AUKUS being scrapped, and said the government has "serious questions" to answer.
"If AUKUS falls over, we will all pay a heavy price," he said in a press conference.
"The Coalition stands ready to work with the Labor to make sure AUKUS is a success."
Sinodinos said he believes it is important not to take the US review as a sign that the pact is "somehow over", and to instead view it as an opportunity to promote greater cooperation between the three countries.
He said AUKUS was a "serious commitment" and one that Australia should not walk back from.
"Any sign that we're backtracking on this will be a sign to people in the region, including potential adversaries, that we're not serious, that we make statements that we're not prepared to follow through," he said.
"The whole point of AUKUS is to be part of the deterrence structure in the region, so that players who may want to do things which are not in our interest understand that we are capable of defending our interests and are prepared to put the resources and the capability into doing that."
Could AUKUS be scrapped — and what would this mean for Australia?
In a post on X, former prime minister Malcolm Turnbull suggested Australia would have the most to lose if the AUKUS deal fell apart.
"The US DoD [Department of Defence] is conducting a review of AUKUS. But Australia, which has the most at stake, has no review," he wrote.
"But Australia, which has the most at stake, has no review. Our Parliament to date has been the least curious and least informed."
Andrews agreed that Australia has the most at stake under the AUKUS agreement due to the country's need for submarines.
He pointed out that Australia's existing conventionally powered submarines are coming towards the end of their life cycle.
"Because we're now 10 years further on than when this started, we still haven't actually got a new vessel in the water that reduces the viable life of our existing submarines.
"So there's a very delicate balance to walk of how we ensure that we keep a functional submarine fleet for Australia and ensuring therefore our maritime security, but also how do we transfer that into this future nuclear power submarine capability."
If the AUKUS deal were to be scrapped, this could leave Australia "back to square one" in terms of submarines and maritime security, Andrews said.
He said rather than scrapping the partnership, it is also possible that the US may opt to delay timelines and deliverable dates for the submarines, which would also be difficult for Australia.
"Where we've found ourselves now is a very narrow pathway of timelines and deliverable dates," Andrews said.
"Anything that pushes those numbers out ... that raises some real challenges for maintaining a functional Australian submarine fleet without spending a lot more money on refurbishing them or something of that nature."
