September 11, 2021, will mark the 20th anniversary of the terrorist attacks on America. President Joe Biden plans to withdraw all U.S. troops from Afghanistan that day. The departure risks democracy, women’s rights, and governance improvements in Afghanistan. It also ensures that the Taliban, the same group that gave al-Qaida a safe haven, remains in control of large swaths of the country.

In a February 2020 agreement with President Donald Trump’s administration, the Taliban agreed to halt attacks and hold peace talks with the Afghan government. But Taliban leaders agreed to do so in exchange for a U.S. commitment to a complete withdrawal by May 1, 2021.

President Biden’s decision keeps U.S. troops in Afghanistan four months longer. However, it does set a firm end to two decades of war. The conflict largely crippled al-Qaida and led to the death of Osama bin Laden, the architect of the September 11 attacks. It also killed more than 2,200 U.S. troops, wounded 20,000, and cost as much as $1 trillion.

U.S. officials had argued against the May 1 deadline. They said the U.S. troop withdrawal should be based on security conditions in Afghanistan—including Taliban attacks and violence—not a certain date.

President Biden disagreed. Though he extended the date beyond that which the former president had set, he decided that a deadline had to be absolute, rather than based on conditions on the ground. “We’re committing today to going to zero” U.S. forces by September 11, and possibly before, he says.

The U.S. forces remaining in Afghanistan after May 1 will be those needed to protect diplomats there.

The decision to stay past the Trump deadline risks payback by the Taliban on U.S. and Afghan forces. Taliban spokesman Zabihullah Mujahed says the Islamist religious militia is waiting for a formal announcement to issue its reaction. The Taliban previously warned the United States of “consequences” if it missed the May 1 deadline.

An intelligence community report issued Tuesday says prospects for a peace deal in Afghanistan are “low.” It warned that “the Taliban is likely to make gains on the battlefield.” If the coalition withdraws support, the report says, the Afghan government will struggle to control the Taliban.

Congressional reaction to the new deadline in the so-called “endless war” is mixed.

Senator Jim Inhofe, the ranking Republican on the Senate Armed Services Committee, slams it as a “reckless and dangerous decision.”

Democratic Senator Tim Kaine says troops should come home, and the U.S. must refocus American national security on more pressing challenges.

Senator Jeanne Shaheen, also a Democrat, tweeted that the United States “has sacrificed too much to bring stability to Afghanistan to leave w/o verifiable assurances of a secure future.”

Over the past year, U.S. military commanders have noted that attacks on U.S. troops have largely paused—but that Taliban attacks on Afghans increased. Commanders have argued that the Taliban have failed to meet the conditions of the peace agreement by continuing attacks on the Afghans and failing to totally cut ties with al-Qaida and other extremist groups.

When President Biden entered the White House in January, he was aware of the deadline. He had time to meet it had he chosen to do so. But in recent weeks, it became clear he was leaning toward missing it.

“It’s going to be hard to meet the May 1 deadline,” Biden said in March. “Just in terms of tactical reasons, it’s hard to get those troops out.” He added, “And if we leave, we’re going to do so in a safe and orderly way.”

(President Joe Biden speaks during a ceremony to honor slain U.S. Capitol Police officer William “Billy” Evans as he lies in honor at the Capitol in Washington, D.C., on Tuesday, April 13, 2021. AP/J. Scott Applewhite)