A landmark security pact to overhaul Australia's navy with American muscle faces growing skepticism, stoked by its eyewatering cost and growing distrust of U.S. President Donald Trump.

But the sweeping deal, which will see Australia buy nuclear-powered submarines from the United States, is just about the only thing not up for debate ahead of Saturday's closely fought election.

Australia, the United States and the United Kingdom signed the AUKUS agreement to great fanfare in 2021, joining forces in a multi-decade effort to balance China's military might.