Final answer:
The U.S. war in Afghanistan (2001–2021) can be described as interventionism, which involves military intervention in another country for specific objectives such as removing the Taliban government and capturing Al-Qaeda members.
Step-by-step explanation:
The U.S. war in Afghanistan (2001–2021) can be described as interventionism, which is a foreign policy approach that involves military intervention in another country for the purpose of achieving specific objectives. In this case, the United States intervened in Afghanistan to remove the Taliban government from power and capture members of Al-Qaeda after the 9/11 attacks. The U.S. maintained a high level of troops in the region and supported the new Afghan government to combat Taliban insurgency.