Resolute Support Mission

Resolute Support Mission (RSM) or Operation Resolute Support was a NATO-led multinational mission in Afghanistan. It began on 1 January 2015 as the successor to the International Security Assistance Force (ISAF), which was completed on 28 December 2014. Pursuant to United Nations Security Council Resolution 2189 of 2014, RSM was a noncombat mission aimed at advising and training Afghan security forces to provide long-term security to the country, under the aegis of the Security and Defence Cooperation Agreement BSA between the United States and Afghanistan, which was originally supposed to run from 1 January 2015 and "shall remain in force until the end of 2024 and beyond" unless terminated with two years' advance notice.

The number of troops and contributing nations would fluctuate throughout RSM's period of activity. In October 2019, RSM had its largest size of troops, which was 17,178. Moreover, throughout 2015, the RSM had its peak of contributing nations, which was 42. The US accounted for the largest contingent, while Italy, Germany, and Turkey served leading roles. Intended to play a temporary and transitionary role, the mission gradually withdrew its forces, which numbered around 10,000 at the start of 2021. On 14 April 2021 via a North Atlantic Council Ministerial Statement, NATO announced a drawdown of RSM troops by 1 May, and the mission was terminated early September 2021. The last remaining RSM troops to leave was a U.S. military unit commanded by Major General Christopher T. Donahue, which were withdrawn on August 30, 2021.