Democrats are coming to President Biden's defense as Afghanistan teeters on the brink of collapse weeks before the U.S. military mission there officially ends, arguing more time wouldn't make any difference.

The Taliban have won control of half of Afghanistan’s 34 provincial capitals, including the country’s second- and third-largest cities, in just a week. Meanwhile, the Biden administration is sending 3,000 troops to help evacuate U.S. diplomats and allies amid rising security fears in Kabul.

The onslaught has Biden’s critics calling for him to immediately reverse course on the withdrawal, which is set to wrap up by the end of the month.

But Democrats argue that, far from being a reason to return, the quick collapse of Afghan government forces without U.S. support shows just how futile the last 20 years, 2,300 troop deaths and $2 trillion have been.

“The complete, utter failure of the Afghan National Army, absent our hand-holding, to defend their country is a blistering indictment of a failed 20-year strategy predicated on the belief that billions of U.S taxpayer dollars could create an effective, democratic central government in a nation that has never had one,” Sen. Chris Murphy (D-Conn.) said this week on the Senate floor.

“Staying one more year in Afghanistan means we stay forever, because if 20 years of laborious training and equipping of the Afghan security forces had this little impact on their ability to fight, then another 50 years wouldn’t change anything,” added Murphy, a close Biden ally.

In a tweet later in the week after the U.S. Embassy in Kabul began an evacuation, Murphy added that “our top priority must be the safety of our people and those Afghans who have most closely helped us,” but still held that “the quickening degradation of security in Afghanistan is just confirmation Biden made the right choice to bring our troops home.”

While the Taliban have had the momentum on the battlefield for months, the past week saw a cascade of victories that made the fall of Kabul appear inevitable sooner than most expected.

It started Aug. 6, when the Taliban won control of their first provincial capital. Each day since has brought more news of the Taliban capturing more capitals while committing atrocities in the process, with the militants winning their biggest prizes Thursday with the fall of Kandahar, the second-largest city in Afghanistan, and Herat, the third-largest.

On Friday, the Taliban also captured the capital of Logar province, putting the insurgents about 50 miles outside of Kabul.

With the security situation rapidly deteriorating, the Biden administration announced Thursday it was evacuating all but a “core” staff at the U.S. Embassy. To help with the evacuation, the military is sending in 3,000 troops — about the same number as withdrew from the country after Biden ordered the pullout in April.

The announcement opened a floodgate of criticism from Republicans, many of whom have opposed the withdrawal from the start.

Senate Minority Leader Mitch McConnell (R-Ky.) held that “Biden’s decisions have us hurtling toward an even worse sequel to the humiliating fall of Saigon in 1975,” while House Armed Services Committee ranking member Mike Rogers (R-Ala.) argued that “America has turned its back on the women and children in Afghanistan.”

Many Democrats, too, have been expressing concern about the fate of the Afghan people, but they have largely avoided criticizing Biden’s withdrawal directly.

House Armed Services Committee Chairman Adam Smith (D-Wash.) called the evacuation of the embassy a “prudent step.” But he added that “while the security situation in Afghanistan is deteriorating, our strategy in the region must continue to evolve.”

Several Democrats reacted to the news of the embassy evacuation by heightening calls to also evacuate Afghans who helped the United States during the war.

“As the Taliban take over the country at breakneck speed, commandeering everything from artillery to helicopters and executing gov’t soldiers who surrender, our Afghan partners, judges, lawyers, teachers, scholars, journalists, human rights defenders — many of them women — are desperate to escape to safety in a third country,” tweeted Sen. Patrick Leahy (D-Vt.).

“This is no time to be questioning whether they qualify for visas. We have a moral obligation to evacuate them and their families,” he added.

In a sign of increasing concern in Congress, Speaker Nancy Pelosi (D-Calif.) has requested the administration brief the full House on the situation in Afghanistan when the chamber returns from recess the week of Aug. 23. The Senate was briefed behind closed doors Monday.

At an appearance in Los Angeles this week, Pelosi hailed the cultural and educational advances Afghan women and girls have made “because the U.S. was there.”

Still, she repeatedly stressed the length of the war and suggested the mission was doomed from the start because “it was not a serious effort,” particularly after “we ignored Afghanistan” to focus on Iraq.

“We did not defeat the Taliban. We routed the Taliban. They headed for the hills and beyond, just waiting to come back. Twenty years,” Pelosi said.

“Our purpose was to make sure it was not a safe haven for global terrorism to hurt the United States,” she added. “We were there almost 20 years. It’s about 20 years.”

Biden shows no sign of reversing course. As recently as Tuesday, the president said he had no regrets about his order to withdraw.

Biden’s chief of staff, Ron Klain, has also been retweeting defenses of Biden’s decision to withdraw, including from former independent Rep. Justin Amash (Mich.).

“The Taliban’s rapid gains in Afghanistan underscore the futility of permanent occupation,” Amash tweeted. “The United States wasn’t able to meaningfully shape circumstances through 20 years of war. We’d have seen the same results had we pulled out 15 years ago or 15 years from now. End the wars.”

Former Defense Secretary Chuck Hagel, who served in the Obama administration, also said this week he still supports the withdrawal.

“I know it was a difficult decision,” Hagel told NPR. “There are going to be consequences for this. It's going to be very difficult. I'm not surprised as to what's happening. But I think we have to ask ourselves, after 20 years, and we start pulling out, and the Taliban just so easily are taking control of these provincial capitals and so much of the country — a lot of mistakes have been made over the years.”