On Sept. 15, only weeks after the United States completed its withdrawal of troops from Afghanistan, the U.S., the United Kingdom and Australia declared the establishment of an enhanced trilateral security partnership — AUKUS.

“We will promote deeper information and technology sharing,” they said in a statement. “We will foster deeper integration of security and defense-related science, technology, industrial bases, and supply chains. And in particular, we will significantly deepen cooperation on a range of security and defense capabilities.”

As the first major initiative under the pact, the U.K. and the U.S. agreed to cooperate on Australia’s acquisition of nuclear-powered submarines.