What is Aukus, the submarine deal between Australia, UK and US?

The multibillion-dollar submarine deal between longtime allies Australia, Britain and the United States has come under scrutiny after the Trump administration said it was reviewing how the deal fits into its heavily promoted “America First” agenda.

The Aukus security pact, Australia’s largest ever defense project, will play a key role in the country’s ability to replace its aging Collins-class submarine fleet and, more importantly, its military posture in the region.

The review is being led by Elbridge Colby, the top adviser to the US defense secretary, who has previously criticized Aukus. In a speech last year, he questioned why the United States was giving away “this valuable asset when we need it most.”

A US defense spokesman said the review was about ensuring “this initiative from the previous administration is consistent with the President’s America First agenda.”

Fears that the review could undermine the agreement were played down by Britain and Australia; Both said the review was a normal process when a new government comes to power.

During a meeting between US President Donald Trump and his Australian counterpart Anthony Albanese on Monday, Trump said the deal was “full steam ahead”.

Billed as a tripartite security partnership, the Aukus deal worth £176 billion ($239 billion; A$368 billion) over 30 years includes two so-called pillars.

The first pillar relates to the supply and delivery of nuclear-powered attack submarines.

Australia will purchase three second-hand Virginia-class submarines from the US from 2032, with the option to purchase two more.

Going forward, the plan is to design and build an entirely new, nuclear-powered submarine model for the UK and Australian navies.

This attack ship will be built in Britain and Australia to a British design, but will use technology from all three countries.

Australia has pledged $3 billion to increase US submarine production rates, and officials have said payments are continuing as planned despite the review.

The second pillar is about allies cooperating on their “advanced capabilities.” This includes sharing military expertise in areas such as long-range hypersonic missiles, undersea robots and artificial intelligence.

The essence of the agreement is believed to be to counter China’s growing presence in the Indo-Pacific region and its role in rising tensions in disputed areas such as the South China Sea.

Although none of the allies directly cited China as the reason for the deal, the three countries spoke of how regional security concerns have “increased significantly” in recent years.

China denounced the deal as “highly irresponsible” when it was first announced.

Foreign ministry spokesman Zhao Lijian said this “seriously undermines regional peace and stability and intensifies the arms race.”

The deal was announced in September 2021 by three former leaders: Australia’s Scott Morrison, Britain’s Boris Johnson and the United States’ Joe Biden.

Britain reviewed the security agreement last year after Sir Keir Starmer’s Labor government won the general election.

For Australia, the deal represents a major advance in its military capabilities. The country is set to become the second country, after Britain, to receive Washington’s elite nuclear propulsion technology.

Such submarines will be able to operate further and faster than the country’s existing diesel-powered fleet. This also means Australia will be able to launch long-range strikes against enemies for the first time.

Under the agreement, Royal Australian Navy sailors will be sent to US and UK submarine bases to learn how to operate nuclear-powered submarines.

The deal will allow both the US and the UK to build a small number of nuclear submarines in Perth, Western Australia, starting in 2027.

Additionally, approximately 7,000 jobs will be created in the UK with the design and construction of the new nuclear-powered submarine fleet in the UK.

The benefits for the US are less obvious; But sharing defense technology could give the country the opportunity to grow its presence in the Asia-Pacific.

Arming Australia has historically been viewed by Washington and Downing Street as necessary to maintain peace in a region far from them.