(The Washington Post) — President Biden’s announcement of a full withdrawal of U.S. troops from Afghanistan by Sept. 11, 2021, is a courageous step that we strongly support. It is also an opportunity to consider the enormous costs of nearly 20 years of war and commit to a better way of promoting Americans’ security and prosperity.

The United States invaded Afghanistan in October 2001 with the support of a strong international coalition and with a clear purpose: to respond to the attacks of Sept. 11, 2001, and make sure that Afghanistan would no longer serve as a base for similar terrorist attacks in the future.

Unfortunately, once that original mission was accomplished, the George W. Bush administration shifted to a longer-term military occupation and state-building operation in Afghanistan. At the same time, it diverted attention and resources toward preparing for the invasion of Iraq, a country that had nothing to do with 9/11.

The results were horrendous — for the people of the region, and for the security of the United States and its partners.

We’ve been sending brave service members — many of whom were just children, or weren’t even born, when the United States first invaded — to fight a mission that long ago strayed from its original purpose. Our veterans know this better than most. A poll from the right-leaning Concerned Veterans for America showed that 67 percent of veterans support a complete withdrawal of troops from Afghanistan. A recent letter from a coalition of veterans’ groups urged Biden to “honor the sacrifices our troops and their families are willing to make on America’s behalf by not asking our women and men in uniform to remain entangled in a conflict with no clear military mission or path to victory.”

Continuing the U.S. military intervention in Afghanistan out of fear that the government might be overrun by the Taliban is the same mind-set that has bogged us down for two decades. If this problem could be solved militarily, it would have been done before now. Withdrawing our troops will allow the United States to refocus on diplomacy as our foreign policy tool of first resort, a key Biden campaign promise. With that in mind, the United States must make it a top diplomatic priority to promote protection for women in Afghanistan. The best way to do that is to ensure they have a seat at the negotiating table, including in continued engagement with the Taliban. We should also use our leverage with other countries to channel their aid to Afghanistan in ways that involve women and young people in the peace process and promote protections for women and girls, as well as other human rights reforms.

Broad inclusion of civil society is essential to ending a conflict in which the most vulnerable civilians continue to be killed. The United States and its partners should coordinate closely with Afghan civil society to increase robust economic development and humanitarian assistance programs, and to help stamp out the corruption that feeds extremism. While our military intervention will end, we must strengthen our commitment to helping Afghans build a better future.

Executing a responsible and comprehensive withdrawal from Afghanistan is an essential first step toward Biden fulfilling his commitment to end “forever wars.” But more work must be done. Most urgently, the United States must use every ounce of its leverage to press Saudi Arabia to end its war of attrition and its blockade against Yemen, where the United Nations warns that 400,000 children could die of starvation this year without immediate action. We must also draw down U.S. forces in Iraq and Syria, rein in the use of drones and other airstrikes, and begin a much more robust debate about whether the worldwide network of U.S. military bases is necessary for our national security. And we must follow through on rejoining the Iran nuclear agreement and promote a broader Middle East regional dialogue to de-escalate conflicts.

More broadly, we must also make sure that in the future the United States uses military force only when force is necessary to protect our national security, when the objective is clear and achievable, and when the president has the informed consent of the American people and the authorization of Congress.

We are encouraged that Biden has recognized the need to repeal the outdated authorizations that have enabled the constant expansion of our wars over the past two decades, and to replace them with much more limited authorizations when and if necessary. We strongly believe that the framers of the Constitution were right to place the power to authorize war with the legislative branch, not the executive, and we intend to move forward to reestablish that important congressional authority.

By ending wars in Afghanistan and around the world, the United States can give our troops the long-overdue homecoming they deserve, usher in a new chapter of American global engagement that prioritizes diplomacy to keep Americans safe, and protect democracy, human rights and the rule of law.