A defensive President Joe Biden called the U.S. airlift to extract more than 120,000 Americans, Afghans, and other allies from Afghanistan to end a 20-year war an “extraordinary success,” though more than 100 Americans and thousands of others were left behind.

Twenty-four hours after the last American C-17 cargo plane roared off from Kabul, Biden spoke to the nation and vigorously defended his decision to end America’s longest war and withdraw all U.S. troops ahead of an Aug. 31 deadline. “I was not going to extend this forever war,” Biden declared Tuesday from the White House. “And I was not going to extend a forever exit.”

Biden has faced tough questions about the way the U.S. went about leaving Afghanistan — a chaotic evacuation with spasms of violence, including a suicide bombing last week that killed 13 American service members and 169 Afghans.

He is under heavy criticism, particularly from Republicans, for his handling of the evacuation. But he said it was inevitable that the final departure from two decades of war, first negotiated with the Taliban for May 1 by former President Donald Trump, would have been difficult, with likely violence, no matter when it was planned and conducted.

“To those asking for the third decade of war in Afghanistan, I ask, ‘What is the vital national interest?’” Biden said. He added, “I simply do not believe that the safety and security of America are enhanced by continuing to deploy thousands of American troops and spending billions of dollars in Afghanistan.”

Asked after the speech about Biden sounding angry at some criticism, White House press secretary Jen Psaki said the president had simply offered his “forceful assessment.”

Biden scoffed at Republicans — and some Democrats — who contend the U.S. would have been better served to maintain a small military footprint in Afghanistan. Before Thursday’s attack, the U.S. military had not suffered a combat casualty since February 2020 — around the time the Trump administration brokered its deal with the Taliban to end the war by May of this year.

Biden said breaking the Trump deal would have restarted a shooting war. He said those who favor remaining at war also fail to recognize the weight of deployment, with a scourge of PTSD, financial struggles, divorce, and other problems for U.S. troops.

“When I hear that we could’ve, should’ve continued the so-called low-grade effort in Afghanistan at low risk to our service members, at low cost, I don’t think enough people understand how much we’ve asked of the 1% of this country to put that uniform on,” Biden said.

In addition to all the questions at home, Biden is also adjusting to a new relationship with the Taliban, the Islamist militant group the U.S. toppled after Sept. 11, 2001, attacks in America, and that is now once again in power in Afghanistan.

Biden has tasked Secretary of State Antony Blinken to coordinate with international partners to hold the Taliban to their promise of safe passage for Americans and others who want to leave in the days ahead.