On July 12, the International Tribunal for the Law of the Sea will issue its ruling on China's claim to practically all of the South China Sea. And already the main military contenders are moving more forces into the region.

China's Maritime Safety Administration announced that naval and air forces will carry out seven days of exercises in an area extending from Hainan to the Paracel Islands off the Vietnamese coast. The exercises will end July 11, just one day before the tribunal's ruling is released, so they will still be around if things get more exciting after that.

They might well get more exciting, because the U.S. Navy's Task Force 70, including aircraft carrier USS Ronald Reagan, has moved to the South China Sea. Its task, says its commander, Rear-Adm. John D. Alexander, is "to maintain the seas open for all to use."