In autumn 2020, a six-week war in the South Caucasus reshaped the dynamics of a decades-old conflict between Azerbaijan and Armenia. The dispute centers on the predominantly Armenian populated region of Nagorno-Karabakh (or Mountainous Karabakh, also known in Armenian as Artsakh) and surrounding territorie sinternationally recognized as part of Azerbaijan. The war has resulted in Azerbaijani control overmuch of the territory it lost to Armenian and Nagorno-Karabakh forces during previous fighting in the 1990s, including a portion of Nagorno-Karabakh and almost all of the surrounding territories. Armenians have retained control over the remaining territory of Nagorno-Karabakh, including the urban center of Stepanakert. A cease-fire agreement mediated by the Russian Federation introduced about 2,000 Russian troops into the conflict zone to serve as peacekeeping forces and to guarantee the security of a land corridor between Armeniaand Nagorno-Karabakh.The local and regional consequences of the autumn 2020 war continue to unfold. The war led to more than 6,000 combatdeaths and more than 150 civilian deaths. It also displaced tens of thousands of people, although many have returned. Inaddition, the Azerbaijani government now is considering how to resettle hundreds of thousands of people who were displaced from the conflict zone in the 1990s, which will require major demining and construction efforts. The 2020 war did not resolve the disputed political status of Nagorno-Karabakh, and it upended a long-standing international conflict resolution framework that emerged after the 1990s conflict. It also led to political turmoil in Armenia and strengthened the government of Azerbaijan. The 2020 war also may increase the influence of regional powers Russia and Turkey, and potentially Iran.Long-standing U.S. policy over several Administrations has been to facilitate a resolution to the Azerbaijan-Armenia conflictthat would achieve a negotiated settlement of Nagorno-Karabakh's political status, peaceably restore Azerbaijani control over territories surrounding Nagorno-Karabakh, and provide security for residents of and returnees to the conflict zone. The autumn 2020 war heightened awareness ofthe danger of mines and new unexploded ordnance in the Nagorno-Karabakhconflict zone and of other humanitarian challenges.In November 2020, the State Department indicated it would provide $5million in humanitarian assistance "to assist people affected by the recent fighting." Prior to the conflict, several Members ofCongress had supported a continuation of demining assistance. Some Members have called for the provision of newassistance related to the conflict and for a review of U.S. military aid to Azerbaijan and the Section 907waiver. In 2021-2022, Congress may address immediate and longer-term consequences of the 2020 war, including assistance needs, the future of international mediation efforts, and changes in regional power dynamics.