Professor Denith Katzman, an academic with the Congressional Research Authority and senior Middle East analyst at the U.S. Congressional Research Department, who has prepared comprehensive files for the Center for Research and Studies, the official provider of information to all members and committees of the U.S. Congress, on Country-U.S. relations in various fields, stressed that his Highness Sheikh Tamim bin Hamad Al Thani's important diplomatic meetings and visits played a distinct role in the development of relations. It has been instrumental in strengthening the means of joint cooperation, discussing the orientations of the two countries towards the latest international issues, and his Highness's face-to-face meetings with prominent officials and ministers of American institutions also contribute to strengthening historical ties and relations, particularly in the field of security and joint military defense, which has been going on since 1980, which witnessed a major development in 1992 through the signing of the official DCA Treaty on Joint Military Cooperation, which organized the presence of U.S. forces and cooperation in the areas of military training and arming deals between Washington and Doha, and extended to counter-terrorism operations, and the vital roles Qatar has played in the Afghan file.