Biden defends Afghanistan pullout deadline

200 Americans still in country after last plane's departure - NBC's Alice Barr reports from Washington, D.C.

WASHINGTON, D.C. (NBC News) - America's longest war is officially over, and it ended much like it began - on note of grim resignation.

Some 200 Americans remained behind when the last U.S. plane departed Afghanistan. Tuesday, as Taliban fighters celebrated their victory, President Joe Biden addressed the nation to explain his determination to still to the pullout deadline.

Snapshots from the end of the 20-year war included a dramatic photo of the last U.S. soldier boarding a plane to leave the country. The final diplomats carried the American flag. Taliban militants celebrated in the streets, and combed through the equipment the U.S. military made inoperable before leaving.

President Biden addressed the nation, discussing the legacy, and the costs, of America's longest war.

"The United States ended 20 years of war in Afghanistan. The longest war in American history," said the President.

Biden faces fierce criticism for the deadly chaos of the final days in Afghanistan, and for sticking to his timeline. As many as 200 Americans were left behind, as well as thousands of Afghans who worked alongside U.S. forces.

"I believe there should be accountability for what I, what I see is probably the biggest failure in American government on a military stage in my lifetime, said. Rep. Kevin McCarthy, (R-Calif.), the minority leader in the U.S. House of Representatives.

The President vowed to keep working to get everyone out, and insisted America is better off without a lasting presence in Afghanistan. He also honored the 13 service members killed last week in the terror attack outside the Kabul airport.

"We owe them and their families a debt of gratitude we can never repay but we should never ever forget," said Biden.

The fallen join more than 2,400 U.S. troops in a bloody conflict that's ending exactly how it begain - with the Taliban in control of Afghanistan.

President Biden had counted on having public sentiment on his side. A new Pew Research poll finds a majority of Americans do support the withdrawal, but also disapprove of the way he handled it.