With its controversial seizure and return of a U.S. underwater drone, Beijing may have inadvertently thrust into the spotlight one of the main motivations behind its ramped-up moves in the South China Sea: the quest to create a safe-haven for its sea-based nuclear deterrent.
Submarines, in particular ballistic missile subs, have long figured prominently in China's desire to match the capabilities and prestige of other major nuclear powers. Slowly but surely, experts say, Beijing has made progress on this front, building a formidable program that began very early in the ruling Communist Party's history.
But securing the credibility of its overall nuclear deterrent has been a challenge.