Relations between Iran and the United States in modern day are turbulent and have a troubled history. They began in the mid-to-late 19th century, when Iran was known to the Western world as Qajar Persia. Persia was very wary of British and Russian colonial interests during the Great Game. By contrast, the United States was seen as a more trustworthy foreign power, and the Americans Arthur Millspaugh and Morgan Shuster were even appointed treasurers-general by the Shahs of the time. During World War II, Iran was invaded by the United Kingdom and the Soviet Union, both US allies, but relations continued to be positive after the war until the later years of the government of Mohammad Mosaddegh, who was overthrown by a coup organized by the Central Intelligence Agency and aided by MI6. This was followed by an era of close alliance between Shah Mohammad Reza Pahlavi's authoritarian regime and the US government, Iran being one of the US's closest allies during the Cold War, which was in turn followed by a dramatic reversal and disagreement between the two countries after the 1979 Iranian Revolution.
The two nations have had no formal diplomatic relations since 7 April 1980. Instead, Pakistan serves as Iran's protecting power in the United States, while Switzerland serves as the United States' protecting power in Iran. Contacts are carried out through the Iranian Interests Section of the Pakistani Embassy in Washington, D.C., and the US Interests Section of the Swiss Embassy in Tehran. In August 2018, Supreme Leader of Iran Ali Khamenei banned direct talks with the United States. According to the US Department of Justice, Iran has since attempted to assassinate US officials and dissidents, including US president Donald Trump.
