In today's world, security is the common ground-the engine spurring international cooperation. The high seas have become an increasingly important venue for expressing nations' shared interests in improving both regional and global security. The following examples illustrate the nature of 21st-century security and the prominent role of maritime forces:
* Proliferation security Initiative. Launched in May 2003 by the Bush administration, the Proliferation Security Initiative (PSI) seeks to coordinate the efforts of participating countries to prevent shipments of weapons of mass destruction (WMD), their delivery systems, and associated materials. A set of interdiction principles forms the basis of the initiative. It is designed to undertake activities consistent with international law and the national laws of the participating states and complements existing nonproliferation regimes. In this spirit, it enhances enforcement, preventing illegal transfers in participating states' territories, airspace, and territorial seas.