In yesterday’s post, we asked “What did the Navy do in the South China Sea?”  That wasn’t a rhetorical question.  The Department of Defense hadn’t yet clearly explained what the USS Lassen did during its recent freedom of navigation operation (FONOP) in the South China Sea.  Nor has it explained the precise legal basis for the operation.

Instead, information has gradually trickled out of the Pentagon.  First, anonymous sources reported that the Lassen “took steps to indicate it was making a lawful innocent passage with no warlike intent,” including turning off fire-control radars and keeping its helicopters grounded.  We found this puzzling:  An innocent-passage transit could inadvertently signal that the United States recognizes a territorial sea near Subi and other artificial islands built on low-tide elevations.  That would contravene the United States’ view (and the orthodox international law view) that low-tide elevations confer no maritime entitlements, even if artificial islands are built on them.

Today, anonymous sources have tossed out a new piece of information—one which may solve the mystery of why the Lassen’s transit was conducted in a manner that appears to have been consistent with innocent passage.  Specifically, Sam LaGrone of USNI News reports that “the feature that required the innocent passage transit was likely Thitu Island, the second largest island in the Spratlys, which has been controlled by the Philippines since the 1970s and home to one of its naval stations.”  Thitu is the site of a Philippine airfield and is apparently home to roughly 100 Philippine civilians.  Under the UN Convention on the Law of the Sea, an island like Thitu, with a permanent civilian population and a fresh water source, commands a 12-nautical-mile territorial sea.

Read more: https://www.lawfareblog.com/answer-innocent-passage-mystery