MELISSA BLOCK, HOST:
We're going to hear now about a picturesque Swedish island in the Baltic Sea - Gotland. For military experts, Gotland is an essential strategic spot. NPR's Ari Shapiro explains this island is at the center of a complex web of alliances in Europe.
ARI SHAPIRO, BYLINE: When I was in Sweden I didn't go looking for a story about Gotland. But the place just kept coming up in interview after interview.
UNIDENTIFIED MAN #1: An island called Gotland.
UNIDENTIFIED MAN #2: Gotland is an extremely important position.
UNIDENTIFIED MAN #1: Sweden is including Gotland, there is no doubt.
SHAPIRO: Northern Europe is a complicated chess board and Gotland is a crucial square. Just to the east of this island are the Baltic states - Latvia, Estonia and Lithuania. These former Soviet Republics are afraid that Russia might try to swallow them up again, just like it did with Crimea in Ukraine. In September President Obama traveled to Estonia and said, we've got your back.
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PRESIDENT BARACK OBAMA: So if in such a moment you ever ask again who will come to help, you'll know the answer - the NATO alliance, including the Armed Forces of the United States of America right here, present now.
SHAPIRO: See, the United States and the Baltics are NATO members. That military alliance says an attack on one member is an attack on all. But Sweden is not part of NATO, which means the island of Gotland isn't either. And whoever controls Gotland has the Baltics in their crosshairs. Keir Giles is a military expert at the Chatham House think tank in London.
KEIR GILES: The island of Gotland is a prime target and has been effectively demilitarized by Sweden over the last decade.
SHAPIRO: Sweden's military is a tiny fraction of its former size. Karlis Neretnieks watched it shrink over his decades-long career in the Swedish military.
KARLIS NERETNIEKS: If the Russians just hypothetically borrow that island...
SHAPIRO: (Laughter). Borrowed without asking.
NERETNIEKS: ...Yes, borrow without asking, then they would dominate the Baltic Sea to such an extent that NATO would have very great difficulties supporting the Baltic states.
SHAPIRO: I asked Sweden's state secretary for the Ministry of Defense whether the Swedish military could keep Russia from grabbing Gotland. Jan Solesund told me...
JAN SOLESUND: Sweden could not prevent that in the long run. I wouldn't think so, to be honest.
SHAPIRO: And if Russia takes Gotland then the U.S. cannot keep its promise to defend the Baltics. Stefan Ring is with the Swedish General Defense Organization, a think tank.
STEFAN RING: Europe is in terrible need for assistance from the United States. We don't have resources enough in Europe to handle a severe situation.
SHAPIRO: Of course, this scenario is hypothetical. But consider - Russian military jets flying in stealth have come within 100 yards of crashing into a Scandinavian passenger plane. Foreign submarines have been spotted in the waters off Stockholm. And in northern Europe, the complex web of military alliances means a local conflict can easily become a regional one and potentially, a global one. Ari Shapiro, NPR News.