It only needed several thousand air and logistic support personnel from the US and other countries for the Afghan army to keep the Taliban at bay. Without that, the US-NATO molded Afghan army, which relied on that, crumbled, its troops knowing they couldn't survive without it. Trump and Biden, despite military advice to the contrary, wanted to pander to politics of war-wearied voters by saying a complete withdrawal. The result is a sanctuary for terrorists, energized Al Quada and ISIS, encouraged Russia and China (look out Taiwan), Israel's strategic reliance on its alliance with the US undermined, and other countries reluctant to depend on the US. Not to mention the slaughter of allied or innocent Afghanis, subjugation and rape of Afghani women, and children raised to hate and fight the West. All that for the political pandering removal of several thousand US and NATO troops!