President Donald Trump on September 7 abruptly cancelled secret meetings with unnamed Taliban representatives and Afghan President Ashraf Ghani. Citing a deadly bombing in Kabul a few days earlier, Trump also said he was cancelling the talks with the Taliban that started a year ago in Qatar.

Those talks focused on four key issues: a Taliban guarantee that it will not allow foreign jihadists to use Afghanistan as a launchpad for attacks outside the country; the complete withdrawal of U.S. and NATO forces; an intra-Afghan dialogue; and a permanent cease-fire. However, Zalmay Khalilzad, U.S. special envoy to Afghanistan, had never been able to arrange even a temporary truce, let alone a permanent cease-fire. The Taliban actually escalated attacks in the weeks prior to Trump’s announcement.

Trump was right to call off the contentious summit, though he probably would have enjoyed the theatrics of a Camp David ceremony reminiscent of Jimmy Carter’s 1978 diplomatic triumph with Menachem Begin and Anwar Sadat. A deal with the Taliban—any deal—would have been violated anyway, so it is just as well that none was signed.

The Taliban see themselves as the Islamic Emirate of Afghanistan—a divinely ordained polity—and they refuse to talk directly to the U.S.-supported government in Kabul, which they regard as inherently illegitimate. Militarily, they are now stronger than at any time since the U.S. military intervention began in 2001. Their position is reminiscent to that of Hanoi in the talks leading up to the 1973 Paris Peace Accords. That agreement’s provisions were immediately broken by the communist side, with no U.S. response. The North Vietnamese Army and Viet Cong gradually expanded areas under their control, and finally entered Saigon in April 1975.

Something similar may happen in Afghanistan after the remaining U.S. forces and NATO personnel are finally withdrawn. If so, it is better that the final act of the drama unfolds without any prior American imprimatur.

The initial objective of U.S. military operations after 9/11 was to remove the Taliban regime and to deny Islamic terrorist networks a key base of operations. That goal was rational, but the method was wrong. A surgical operation against al-Qae da, a brief occupation of Kabul, and a vigorous supervision regime based on drones and missiles should have been enough to demonstrate American resolve, to neutralize terrorist threats, and to satisfy the public opinion at home.

Instead, the George W. Bush administration indulged in an open-ended exercise in nation building that was underpinned by grossly wasteful development programs. By the end of his second mandate, the situation on the ground had settled into a stalemate. The Taliban were able to reestablish their permanent presence in the majority Pashtun areas in the south; the allies held the cities and kept the main roads open; and Hamid Karzai and his corrupt cronies pretended to be a government.

The Obama administration decided to give Afghanistan higher priority, however. One goal was to transfer responsibility for security to the Afghan National Army and police; the other was to arrange a power-sharing agreement that would bring the Taliban into the political mainstream. Both goals were unrealistic and achieving one without the other was neither useful nor possible.

President Trump’s Afghanistan policy, established in August 2017, was to settle for a compromise between the all-out escalation advocated by some of his generals and the complete disengagement he had favored on the campaign trail. The result was predictable: an open-ended continuation of the unstable stalemate.

In the final year of his first mandate, Trump should follow his instincts: withdraw U.S. forces and Afghanize the war. “Tens of thousands of people will be killed here if the Americans pack and get out,” Afghan parliamentarian Mirwais Yasini warned seven years ago; the Taliban would seize power again in a matter of weeks. His warning is still valid—but that is an Afghan problem.

Ensuring lasting peace, stability, and national reconciliation in Afghanistan is neither essential to U.S. security nor attainable. Therefore, Afghanistan should be allowed to revert to its usual state of Hobbesian pre-modernity. The lessons of fruitless intervention in Afghanistan, not only of America’s but of the 1979 Soviet campaign and two disastrous 19th-century British interventions, should be Washington’s guide for the future.

The Afghan mission is over. From now on the Trump administration should focus on the technicalities of a swift withdrawal and on contingency plans to neutralize from afar any future terrorist threat, using drones and missiles. All along, the Taliban only needed to survive to win. They have survived.