actors in international trade such as Singapore and the United Arab Emirates, as well as countries such as Turkey and the Republic of Korea, who are geographically close to states designated by United Nations Security Council resolutions as proliferation threats. Eleven nations have signed bilateral Mutual Shipboarding Agreements with the United States, allowing the mutual expedition of shipboarding requests for ships under those nations' flags. The Eleven are the Antigua and Barbuda, Bahamas, Belize, Croatia, Cyprus, Liberia, Malta, the Marshall Islands, Mongolia, Panama and St. Vincent and the Grenadines. Each of these nations maintains a large number of commercial vessels on their registries, and are often considered flag of convenience states. In April 2009, at a speech in Prague, Czech Republic, newly inaugurated President Barack Obama announced that he planned to transform the PSI into a "durable international institution", indicating that US promotion of the initiative would remain non-partisan and cross over from the previous administration. Indeed, Obama had made the strengthening of the PSI one of his campaign promises in the Presidential election of 2008 and continued to promote the PSI through the 2010 White House Nuclear Security Strategy. The 2013 PSI High Level Political Meeting facilitated the adoption of a set of four Joint Statements, advancing cooperation among PSI endorsing states toward: - Ensuring a Robust Initiative - Enhancing Critical Interdiction Capabilities and Practices - Strengthening Authorities for Action - Expanding Strategic Communications Progress on implementation was reviewed at the PSI Mid-Level Political Meeting in January 2016, hosted in Washington, DC. Another PSI High Level Political Meeting will be hosted in France in 2018. The PSI has evolved considerably since 2003, embracing a much wider array of proliferation security issues, such as customs enforcement, export controls, proliferation finance, and intangible transfers of technology. Given its broad and flexible mandate, the PSI now plays a vital role in advancing proliferation security norms and standards of practice. Participation The primary role of PSI participants is to abide by the Statement of Interdiction Principles, with the primary purpose of interdicting subject weapons and materials. Additionally, participants are recommended to enact legal statutes to facilitate effective interdiction and seizure of such items. Finally, participants are to take measures to ensure that their national facilities are not utilized to transfer illicit weapon cargoes. The PSI also supports the maintenance of an informal network of transgovernmental linkages that sustain cooperation outside of the formal