For more than a decade, China has deployed warships to the Gulf of Aden and the waters off Somalia. For much of that time, piracy in the region has been in sharp decline. Now, however, with attacks at their highest reported level since 2013 and other naval forces engaged in crises elsewhere, Beijing’s long-running escort mission is being tested. The renewed attacks and hijacking for ransom come as the US Navy focuses on operations connected to the war on Iran, and India sends ships towards the...