America’s longest war is ending. A nation is left wondering whether it was all worth it.

America’s “forever war” in Afghanistan outlasted the first three commanders in chief of this century. But this week, Joe Biden is set to become the president who imposes closure on the US’ role in the bloody, intractable conflict. Twenty years after the 9/11 attacks — plotted by al-Qaeda from Afghan soil — plunged the United States into a fractured graveyard of empires, the US pull-out will be complete within days, multiple military sources told CNN.

As many as 1,000 troops could remain to guard the American embassy in Kabul, and to protect the airport — a lifeline for the fragile government and its armed forces who are destined to carry on fight the perpetual war that raged before the US arrived and will continue after it leaves. But the American operation — launched by President George W. Bush when New York’s Twin Towers and the Pentagon lay in ruins — is functionally over.

In a wider strategic sense, the withdrawal underscores how the War on Terror — which US and allied leaders insisted would be the organizing principle of international relations for decades to come — has faded as the dominant priority.