The Case for a Pacific Defense Pact
“A collective defense pact would deliver where the current mechanisms fall short. Getting there would not require a panregional security organization such as NATO, which grew from 12 original members to over 30. Instead, the logical starting point for Washington is to form a pact with the three partners that are most strategically aligned and have the fastest-growing and most robust combined military cooperation: Australia, Japan, and the Philippines.”
“Critical U.S. partners such as India and Singapore would not be expected to join at the outset but could still participate in certain activities as observers or in some other nonmember capacity, as is common in regional groupings. The inclusion of Taiwan would not be possible or advisable under current U.S. policy, nor would it be acceptable to the other members of the pact. As for the United States’ European allies, they are neither politically nor militarily ready to join as full members right now, but that option could be considered in the future, under different circumstances. Larger defense budgets in Europe could produce militaries with more global reach, provided the continent itself is secure and at peace.”
https://www.foreignaffairs.com/china/case-pacific-defense-pact