For years, pundits referred derisively to ASEAN as a "talk shop." Over just a six-year history, however, the eighteen-country ASEAN Defence Ministers' Meeting-Plus (ADMM-Plus) has moved past this perception to serve as a key mechanism for regional cooperation and become an engagement priority for the U.S. Department of Defense. By working with the ADMM-Plus, the Defense Department supports the broader U.S. government commitment to political stability and economic growth in the Asia-Pacific, as well as pursing practical opportunities for familiarization and interoperability with allied and partner militaries-all while respecting the principle of ASEAN centrality.First, it must be clarified that this multilateral participation does not replace historical U.S. relationships. The Department of Defense will continue to actively maintain and expand bilateral treaty alliances and partnerships in the region. U.S. Pacific Command (PACOM) has also initiated trilateral and quadrilateral defense discussions with key partners. To supplement those relationships, however, ASEAN-centered relationships are of growing utility as the strategic terrain evolves. In a region affected by frequent natural disasters, the threat of terrorism, rival maritime claims, illegal fishing, food security challenges, environmental degradation, and other shared threats, multilateral responses are crucial. And while the ADMM-Plus is the most direct avenue for military engagement in ASEAN, the Department of Defense will also continue to play a role in supporting other ASEAN-centered mechanisms, such as the ASEAN Regional Forum (ARF), to increase civil-military cooperation and integration.These emerging patterns are a natural continuation of the U.S. commitment to the region over the greater part of a century. The United States was formally elevated to the status of strategic dialogue partner to ASEAN last November. Therefore, engagement at every opportunity, including through ASEAN's defense-led mechanisms, allows the United States to solidify its current and future role as an Asia-Pacific country. This essay describes how involvement in the ADMM-Plus allows the Department of Defense to complement whole-of-government approaches to ASEAN engagement. It also describes some of the reasons that the ADMM-Plus, in particular, serves as the priority avenue for the Department of Defense's security cooperation with ASEAN and discusses internal challenges that the department faces in these efforts.The ADMM-Plus and Other ASEAN Mechanisms: A Team ApproachEngagement with the ADMM-Plus allows the Department of Defense to support broader interagency efforts. The cohesion of ASEAN into its current form over the last several decades has enhanced the regional security architecture of not just Southeast Asia but the Asia-Pacific writ large. The ten ASEAN member states have managed to not only create a functioning coordination mechanism for their own subregion; they have placed themselves squarely in the middle of transregional discussions involving dialogue partners spanning Northeast Asia, South Asia, and Oceania.The broader U.S. government actively supports ASEAN's regional centrality and leadership role. The ASEAN Economic Community and ASEAN Social-Cultural Community can only really be implemented in an ASEAN Political-Security Community with wide-reaching stability and security. By providing a forum in which defense policy issues can be discussed, and in which habits of practical multilateral security cooperation can be established, the ADMM-Plus plays an important role in improving the regional political-security situation, thereby having a positive impact on the broader economic and sociocultural spheres.How does the ADMM-Plus relate to and compare with other ASEAN-centered mechanisms? First, the ADMM-Plus is the mechanism designated for defense engagement by ASEAN dialogue partners. Although interagency coordination is important, and the Department of Defense will support those efforts, militaries must first reach out to each other, with civil-military engagement occurring under the appropriate civilian leadership. …