Foreign policy, for better or worse, is always an extension of a nation’s domestic politics. The arc of America’s war in Afghanistan is a testament to this reality – the story of a superpower that overreached, slowly came to terms with the limits of its capacity to shape events abroad, and withdrew in the wake of raging dysfunction at home. Viewed through this prism, President Joe Biden’s decisive yet chaotic withdrawal comes into focus.

Foreign policy, for better or worse, is always an extension of a nation’s domestic politics. The arc of America’s war in Afghanistan is a testament to this reality – the story of a superpower that overreached, slowly came to terms with the limits of its capacity to shape events abroad, and withdrew in the wake of raging dysfunction at home. Viewed through this prism, President Joe Biden’s decisive yet chaotic withdrawal comes into focus.

The story begins with trauma and hubris. On September 11 2001, American power was at its high-water mark. The globalization of open markets, democratic governance, and the US-led international order had shaped the previous decade. The spectre of nuclear war had been lifted, the ideological debates of the 20th century settled. To Americans, mass violence was something that took place along the periphery of the post-cold war world. And then suddenly, the periphery struck the centres of American power, killing thousands.

As a young New Yorker, I saw a plane plough into the World Trade Center and the first tower fall. I smelled the air, acrid from burnt steel and death, for days afterwards. Like most Americans, I assumed my government would retaliate against the people who did this. But President George W Bush’s administration had larger ambitions. Speaking days after 9/11 to an audience that included the US Congress and British prime minister, Tony Blair, Bush declared: “Our war on terror begins with al-Qaida, but it does not end there. It will not end until every terrorist group of global reach has been found, stopped, and defeated.”

Out of this trauma, the American public supported Bush’s declaration of a “war on terror” as a kind of blank slate, with details to be filled in by his administration. Most Americans were afraid, wanted to be protected, and were rooting for their government to succeed. Within weeks, Congress granted Bush open-ended powers to wage war, passed the Patriot Act, and set to work reconstructing the US national security apparatus. But rapidly toppling the Taliban and scattering al-Qaida did not meet the ambitions of Bush, who had likened this conflict to the second world war and the cold war. Instead of wiping out al-Qaida’s leadership (who escaped into Pakistan) and coming home, the Bush administration decided to build a new Afghan government and then promptly shifted its attention to Iraq – while tarring its political opponents as weak and unpatriotic. The die was cast.