WASHINGTON – The United States is forming a security partnership with Australia and the United Kingdom that will allow them to share defense technology in a move that could be seen as sending a message to an aggressive China . The new partnership, which will be known as AUKUS, will enable the three countries to share artificial intelligence, undersea capabilities and other advanced technologies and deepen cooperation on a range of defense capabilities in the Indo-Pacific region. One of the working group’s first initiatives will be to help Australia develop a fleet of nuclear-powered submarines, which Australian media reports could...