Sweden became the newest member of NATO earlier this month, joining 31 nations in the security alliance, including the United States. Well, make that 49 of the 50 United States.

Because in a quirk of geography and history, Hawaii is not technically covered by the NATO pact.

If a foreign power attacked Hawaii – say the US Navy’s base at Pearl Harbor or the headquarters of the Indo-Pacific Command northwest of Honolulu – the members of the North Atlantic Treaty Organization would not be obligated to rise to the Aloha State’s defense.

“It’s the weirdest thing,” says David Santoro, president of the Pacific Forum think tank in Honolulu, who added that even most Hawaii residents have no idea their state is technically adrift of the alliance.

“People tend to assume Hawaii is part of the US and therefore it’s covered by NATO,” he says.

But, he concedes, the tip-off is in the alliance’s name – North Atlantic Treaty Organization.

Hawaii is, of course, in the Pacific, and unlike California, Colorado or Alaska, the 50th state is not part of the continental US that reaches the North Atlantic Ocean on its eastern shores.

“The argument for not including Hawaii is simply that it’s not part of North America,” Santoro says.

The exception is spelled out in the Washington Treaty, the document that established NATO in 1949, a decade before Hawaii became a state.

While Article 5 of the treaty provides for collective self-defense in the event of a military attack on any

NATO’s European member states

The North Atlantic Treaty Organization – NATO – was founded by 12 countries in 1949. The alliance expanded to Eastern Europe after the collapse of the Soviet Union in 1991. Finland and Sweden applied to join in May 2022 following Russia’s invasion of Ukraine.