Asks Colin Clark: Why has Chinese foreign policy made a sudden turnabout from ‘peaceful development’ to ‘belligerence’? I would add: is such a swerve really ‘unexpected,’ as the title of his AOL Defense column indicates? He points out that several events have disturbed the equilibrium along China’s maritime frontiers in recent weeks. Vietnam and India concluded an agreement to explore for oil in South China Sea waters claimed by Hanoi and Beijing. Japan and the Philippines held consultations, declaring a joint interest in sea-lane security in the South China Sea. The Obama administration announced that it would upgrade aging F-16 A/B fighter jets for Taiwan, although Washington stopped short of transferring new model F-16s to the increasingly outmatched Taiwan Air Force. It’s been an eventful time, even by the standards set in the past couple of years.