Short answers, pulled from the story.
The final text of the Australia, New Zealand, United States Security Treaty concluded at San Francisco on the 1st of September 1951. The agreement entered into force on the 29th of April 1952.
Washington suspended treaty obligations because Prime Minister David Lange barred nuclear-powered or nuclear-armed ships from using New Zealand ports following the Labour Party victory in 1984. This refusal effectively blocked all US Navy vessels from entering New Zealand waters despite an unofficial invitation.
The guided-missile destroyer USS Sampson became the first US warship to visit New Zealand in thirty-three years during celebrations held over the weekend of 19, the 21st of November 2016. This visit occurred under existing nuclear restrictions requiring satisfaction that visiting ships were not armed or powered by nuclear means.
Unlike the North Atlantic Treaty Organization, the pact contained no integrated defence structure or dedicated forces. It lacked binding enforcement mechanisms found in NATO while obligating parties to maintain their capacity to resist armed attack and consult with one another on security matters throughout the Pacific region.
Australia deployed 2,500 American troops to Darwin following announcements made at Canberra meetings between President Obama and Prime Minister Julia Gillard in November 2011. This deployment followed the signing of the AUKUS agreement in late 2021 which created a trilateral security partnership focused on submarine capabilities.