Taliban fighters can be seen in recently released videos celebrating the seizure of US Humvees, tanks and assault weapons from Afghan security forces as the Biden administration begins its troop withdrawal before the Sept. 11 deadline. The Taliban have been capturing key districts in the northern part of the war-torn country — including Kandahar and Badakhshan — with little or no resistance from Afghan national forces since the US announced the timetable for the departure in April. They are extending their control of Afghanistan from their southern strongholds by filling the void left by the departing US forces. More than...