By ABC North America bureau chief Jade Macmillan, in Washington DC
Australia's plan to acquire nuclear-powered submarines under the AUKUS agreement has cleared a major hurdle, with a package of legislation passing the US Senate.
The bills authorise the sale of at least three Virginia-class submarines to Australia and formally allow the federal government to make a US$3 billion (NZ$4.8bn) payment to accelerate production in US shipyards.
They also pave the way for the relaxation of export controls, allowing the transfer of sensitive technology to Australia, and allow private defence contractors to train in the US.
The legislation - which is included in an annual US defence policy package - still needs to be approved by the House of Representatives, but its passage through the Senate is a significant step forward.
It had been held up by concerns in Congress that the US could not afford to transfer submarines to Australia while it was struggling to meet its own production targets.
President Joe Biden sought to address those fears by requesting a further $3.4 billion in US funding for the American submarine industrial base.
He later assured Prime Minister Anthony Albanese he was confident the AUKUS legislation would get through.
The long road ahead for Australian subs
The first Virginia-class submarine is not expected to be transferred to Australia until the early 2030s.
The legislation states that 270 days before that happens, a future US president must certify that the move is consistent with US foreign policy interests and would not "degrade" its own undersea capability.
It also requires the president to notify congressional leadership one month before the first submarine is delivered that Australia has achieved what is known as 'Submarine Rotational Force West' - a plan to rotate up to four American and one British sub out of Western Australia.
The AUKUS bills formed part of the National Defense Authorization Act (NDAA), a major piece of legislation considered by Congress each year.
It was passed overwhelmingly by the Senate, 87 votes to 13.
Leaders from both parties spoke in favour of the AUKUS deal ahead of the vote, with Democratic majority leader Chuck Schumer arguing it was a "game changer".
"It will create a new fleet of nuclear-powered submarines to counter the Chinese Communist Party's threat and influence in the Pacific," he told the chamber.
- This story was first published by the ABC.