The conflicts in Yemen and U.S. national security -- Introduction -- The Yemeni political system in crisis -- Yemen's security concerns with the Houthi rebellion and the Southern secessionists -- The Houthi rebellion -- The Southern movement -- Yemeni regional politics and the relationship with Saudi Arabia -- The origins and development of the Al-Qaeda presence in Yemen -- The intensification and expansion of the Al-Qaeda threat in Yemen -- U.S. interests and policies involving Yemen -- Conclusion and recommendations.