Eight Trillion. 39 million. 2,372. 4,431. One. Those numbers are, respectively, the cost of the War on Terror in dollars, the number of refugees displaced by American wars, the American death toll in Afghanistan, and the American death toll in Iraq. “One” refers to the wedding we bombed in a drone strike. Put into numbers, the toll that our country’s post-9/11 foreign policy has taken on the world is something akin to stunning.

But the cost of the War on Terror cannot be summed up with cold statistics. It transformed the American nation in profound and pernicious ways, and destroyed the moral standing we had long held as the world’s “indispensable nation.” America is a less free, less solvent and less respected country than we were before the Twin Towers came down. And the devastation the wars in Iraq and Afghanistan, as well as drone strikes in seven countries, have wrought upon the Arab-Muslim world is even greater in scale and destructiveness.

The War on Terror was sparked by a characteristically American, and human, overreaction to the threat of Jihadist terrorism. From the Alien and Sedition Acts to McCarthyism to the law misnamed PATRIOT, the United States has inflated foreign threats and allowed its government to diminish the civil liberties of its citizens and immigrant residents. In the Adams administration, we considered internment for French immigrants. Under Police Commissioner Ray Kelly, the N.Y.P.D. conducted surveillance of mosques. The government waterboarded one detainee 80 times.

Yet it is clear today that violent Islamic terrorism posed less of a threat to America than was widely assumed in the wake of 9/11. Since that day, more Americans have been killed by white-supremacist domestic terrorists than by foreign jihadists. The atmosphere in the early Bush administration was hysterical. One “expert” claimed we would “lose a city,” and even in little Raleigh, North Carolina, where I lived at the time, citizens believed that al-Qaeda was distributing anthrax in the mail. In retrospect it is clear that though we were under attack by evil men, our civilization was not threatened at its core.

The War on Terror was launched against one terrorist network and ended up spawning a far more brutal one–ISIS. The Islamic State’s brutality is so extreme that it has appalled even some early al-Qaeda leaders. Dovetailing with a project aimed toward military hegemony in the Middle East, the NATO-led intervention in Libya created a failed state with open slave markets. Afghanistan’s government collapsed weeks after the United States completed its withdrawal.

The end of the War on Terror is hardly in site. President Biden’s administration has promised to continue missile strikes on Taliban-controlled Afghanistan, and the national security state’s enthusiasm for death by drone seems undimmed. But even if this era ends in my lifetime, its scars will be deep, and the wound it opened around the world may never fully heal.