NOW on its 39th iteration, the annual joint military exercise between the Philippines and the United States is one of the world's oldest. Now known as 'Balikatan,' a Filipino word meaning 'shoulder to shoulder,' it is the biggest of the several military exercises, in the field or classroom, held annually by the two countries in implementation of their 1951 Mutual Defense Treaty. A main aim of the exercises is to ensure interoperability between the two countries' forces whenever they have to defend themselves and fight a common adversary. Balikatan is, in a sense, always new as it tries to respond to changing challenges in a changing global or regional environment.

Balikatan has always been participated in by members of the three main services and special services of the armed forces of both countries. When threats to the country's security were perceived as only internal, the Navy seldom took part. The 17,000 or more participants of this year's Balikatan come not only from the Armed Forces but, for the first time, also come from the Coast Guard. The Coast Guard's participation is a sign of a critical change that has swept the Indo-Pacific region, to which we belong.