Our treaty with the Marshall Islands (formerly part of the US Trust Territory of the Pacific Islands, and independent since 1986) provides that the United States takes full responsibility for their defense. In the words of the State Department:
The United States has full authority and responsibility for security and defense of the Marshall Islands, and the Government of the Marshall Islands is obligated to refrain from taking actions that would be incompatible with these security and defense responsibilities.
But when a Marshall Islands ship was seized by Iran, the Pentagon announced:
You thought that treaty meant something to the Obama administration? Think again.
UPDATE: David Kopel gives the Pentagon’s position more thorough consideration than it deserves, and finds it wanting.
(Via Hot Air.)