From the Summary: "Bahrain is a small island nation, ruled by a hereditary monarchy, that is in a partnership with other Arab monarchies of the Persian Gulf called the Gulf Cooperation Council (GCC: Saudi Arabia, Kuwait, United Arab Emirates, Bahrain, Qatar, and Oman). Bahrain is led by King Hamad bin Isa Al Khalifa, who succeeded his father, Shaykh Isa bin Salman Al Khalifa, upon his death in 1999. U.S.-Bahrain ties are long-standing and have deepened over the past four decades as the Gulf region has become highly volatile. The country has hosted a U.S. naval command headquarters for the Gulf region since 1948, and the United States and Bahrain have had a formal Defense Cooperation Agreement (DCA) since 1991. In 2004, Bahrain was designated by the United States as a 'major non-NATO ally.' There are nearly 5,000 U.S. forces, mostly Navy, serving at the naval facility and other bases in Bahrain, and the country is a significant buyer of U.S.-made arms. In 2014, Bahrain joined the U.S.-led coalition combatting the Islamic State and flew strikes against the group's fighters in Syria that year."
CRS Report for Congress, 95-1013
Congressional Research Service: https://crsreports.congress.gov/