Biden, saying it is ‘time to end America’s longest war,’ declares troops will be out of Afghanistan by Sept. 11.

President Biden formally ended the 20-year, largely unsuccessful American effort to remake Afghanistan, declaring from the White House on Wednesday afternoon that he would withdraw the remaining few thousand United States troops in the country by Sept. 11 and refocus American attention elsewhere.

“It’s time to end America’s longest war,” he said. “It’s time for America’s troops to come home.”

He warned the Taliban that if American forces are attacked on the way out of the country, “we’re going to defend ourselves and our partners with all the tools at our disposal.”

Speaking from the Treaty Room in the White House, Mr. Biden made the case that the United States had only one real task in the country: ousting Al Qaeda and making sure that the country would never again be the launching pad for a terrorist attack on the United States, as it was on Sept. 11, 2001.

In announcing his decision, the president made only passing mention of the other objectives that had been used over the years to justify the continued American military presence: building a stable democracy, eradicating corruption and the drug trade, assuring an education for girls and opportunity for women, and supporting peace talks between the Taliban and the government.

All were noble goals, he suggested, but keeping American troops in the country until they were accomplished was a formula for a perpetual presence after the killing of Al Qaeda’s leader, Osama bin Laden. “We delivered justice to bin Laden a decade ago,” he said. “And we’ve stayed in Afghanistan for a decade since.”

Saying he was the fourth president to deal with the question of troops in Afghanistan, two Republicans and two Democrats, he added, “I will not pass this responsibility on to a fifth.”

For the United States, Mr. Biden’s announcement was a humbling moment. The Afghan war was not only the longest in American history, it was one of the costliest — more than $2 trillion. Nearly 2,400 American service members were killed, more than 20,700 wounded.

And while the United States accomplished the key strategic objective that led President George W. Bush to order the invasion of the country in October 2001 — ousting Al Qaeda and preventing it from using Afghanistan’s mountains and deserts to launch another attack on the United States — few of the broader, shifting goals of building the nation proved lasting.

Mr. Biden is the first president to have rejected the Pentagon’s recommendations that any withdrawal be “conditions based,” meaning that security would have to be assured on the ground before Americans pulled back. To do otherwise, military officials have long argued, would be to signal to the Taliban to just wait out the Americans — after which, they would face little opposition to taking further control, and perhaps threatening Kabul, the capital.

But some architects of the policy agreed that it was time to go. Douglas Lute, a retired general who ran Afghan policy on the National Security Council for Mr. Bush and then for President Barack Obama, wrote for CNN with Charles A. Kupchan on Wednesday that “those who argue that we need to stay in Afghanistan to thwart attacks against the homeland are wrong,” because the terror threat from inside the country “has been dramatically reduced in the last 20 years.”

And Mr. Biden has made clear that Afghanistan has become a drain on resources and attention, at a moment he wants to focus on inequality and investments in infrastructure and new technology at home, and far more complex threats from China and other adversaries. In so doing, he is joining the British and the Soviets, among others, who thought they could reshape Afghanistan, only to discover the cost was unacceptably high.

The nation’s top intelligence officials faced a congressional panel on Wednesday for the first time in two years to discuss global threats faced by the United States, fielding questions on China, Russia, Iran and more.

Lawmakers said they would press the intelligence chiefs on China, Russia, Iran, as well as domestic extremism, cyberattacks and election interference. Senators are also likely to raise prospects for continued violence in Afghanistan now that President Biden has decided to pull out troops by September. The intelligence community’s annual threat assessment report released ahead of the hearing emphasized the growing challenge of China and the continuing threat from Russia, though it acknowledged that both powers wanted to avoid direct confrontation with the United States. “China is employing a comprehensive approach to demonstrate its growing strength and compel regional neighbors to acquiesce to Beijing’s preferences,” Avril B. Haines, the director of national intelligence, told senators.

The F.B.I. director, Christopher A. Wray, also emphasized the threat from China. “We’re opening a new investigation into China every 10 hours,” he said of the bureau, “and I can assure the committee that’s not because our folks don’t have anything to do with their time.”

In his opening statement, Senator Mark Warner, the Virginia Democrat who leads the committee, emphasized that the challenge was not from the Chinese people, and especially not with Asian-Americans, but Beijing’s communist government. Ms. Haines was joined at the hearing by four other agency directors: Mr. Wray, William J. Burns of the C.I.A., Gen. Paul M. Nakasone of the National Security Agency and Lt. Gen. Scott D. Berrier of the Defense Intelligence Agency. Both Russia and China have been blamed for conducting cyberoperations that compromised broad swaths of the software supply chain. Lawmakers said they would press Ms. Haines and the other intelligence officials on the Russian hacking, which penetrated nine federal agencies, and another by China that compromised Microsoft Exchange servers. The Biden administration is expected to respond to the Russian hacking soon.

Ms. Haines said Russia uses hacks to sow discord and threaten America and its allies. “Russia is becoming increasingly adept at leveraging its technological prowess to develop asymmetric options in both the military and cyber spheres in order to give itself the ability to push back and force the United States to accommodate its interests,” she said.

Biden administration officials have emphasized that they want the intelligence agencies to take a wider view of threats, and the officials are expected to discuss the impacts of climate change on national security. The threats report linked surges in migration to both the pandemic and climate change.

Ms. Haines noted that another recent intelligence report on global trends highlighted how the pandemic and climate change, along with technological change, were testing “the resilience and adaptability” of society. The “looming disequilibrium,” she said, compels intelligence agencies to broaden their definition of national security. https://www.nytimes.com/live/2021/04/14/us/joe-biden-news