From the Document: "Since May 2019, U.S.-Iran tensions have escalated significantly, but have stopped short of erupting into armed conflict. The Trump Administration, following its 2018 withdrawal from the 2015 multilateral nuclear agreement with Iran (Joint Comprehensive Plan of Action, JCPOA), has taken several steps in its campaign of applying 'maximum pressure' on Iran. Iran and Iranlinked forces have attacked and seized commercial ships, caused destruction of some critical infrastructure in the Arab states of the Persian Gulf, and posed threats to U.S. forces and interests, including downing a U.S. unmanned aerial vehicle. Iran has exceeded some nuclear limitations stipulated in the JCPOA. The Administration has sent additional military assets to the region to try to deter future Iranian actions and has continued to impose additional U.S. sanctions on Iran."
CRS Report for Congress, R45795
Congressional Research Service: https://crsreports.congress.gov/