This chapter details the U.S. and EU-led mediation efforts in the Nagorno-Karabakh conflict from 2021 to 2023, culminating in the region’s demise and ethnic cleansing of the Armenian population. The OSCE Minsk Group was sidelined, with the EU and U.S. attempting to broker a peace deal between Armenia and Azerbaijan. Armenian Prime Minister Nikol Pashinyan made significant concessions, including recognizing Azerbaijan’s territorial integrity as encompassing Nagorno-Karabakh, despite internal opposition. Meanwhile, Azerbaijan, with backing from Türkiye and new relevance to the EU for gas supply, ramped up military pressure. Russia’s influence waned, particularly after its invasion of Ukraine in 2022 and failure to intervene when Azerbaijani forces launched attacks on sovereign Armenian territory. Azerbaijan’s nine-month blockade of the Lachin Corridor, beginning in December 2022, created a severe humanitarian crisis. This was followed by a military offensive in September 2023, which resulted in the swift surrender of Nagorno-Karabakh authorities and the exodus of the entire indigenous Armenian population. Experts characterized this as ethnic cleansing and genocide. The enclave’s leaders were detained by Azerbaijan with illegal military trials ongoing as of October 2025. A U.S.-brokered initiative resulted in a Joint Declaration and an Agreement on Establishment of Peace and Inter-State Relations in August 2025, dismissing the OSCE Minsk Group, and initialing, not signing until further measures, a “peace agreement.” However, this framework was criticized for ignoring the rights of the displaced Armenians and the fate of Armenian prisoners in Baku, leaving major gaps that threaten lasting stability. The agreement also included the U.S.-led “Trump Route for International Peace and Prosperity” (TRIPP) linking Azerbaijan with its exclave Nakhichevan through Armenia’s southern region.