After enlisting in the U.S. military against his family’s wishes, Chicago native Tom Amenta said he found himself in “middle-of-nowhere,” Afghanistan, in 2002 as an Army Ranger in a remote area some 15 minutes from the border with Pakistan. He was fighting the initial battles of a war that few knew would stretch on for 20 years.

Now 40 and retired from the military, he felt anger foam inside as he watched the evening news on Thursday while on a work trip to Pennsylvania.

Headline after headline broadcast the latest gains by Taliban fighters, who have seized control of more than a dozen of the country’s provincial capitals as the Afghan government inches closer to collapse in the final days of the U.S. withdrawal. He was riveted in horror by news of fighters committing suspected war crimes against civilians or Afghan troops.

Friends who had been killed there came to mind, including NFL star Pat Tillman. Fond memories of former Afghan colleagues, such as interpreters, who remained in the country and whose fates he didn’t know, also resurfaced.

"The Afghanistan Papers" author Craig Whitlock explains how presidents misled the public about the war in Afghanistan for nearly two decades. (Joy Yi/The Washington Post)

“It makes me angry, really angry,” Amenta said of the U.S. withdrawal, lamenting the billions upon billions of dollars spent on the war effort — not to mention the emotional, financial and human toll suffered by thousands of Americans who served or sent their loved ones to fight in Afghanistan.

Afghanistan “has never had a clean solution. But now that it’s gotten hard, we’re just going to bounce? It doesn’t make it right,” he said in a phone interview.

Amenta is one of many veterans voicing frustration over the Taliban’s faster-than-expected comeback, reflecting how deeply the conflict resonates around the world. About four dozen countries have sent troops in support of the United States, which, with 2,300 killed while serving, has spilled the most blood in the war, apart from Afghans themselves.

Amenta recounted memories of Jay A. Blessing of Tacoma, Wash., a goofy friend and fellow Army Ranger who used to put hot sauce on everything: “I mean, literally everything. He put hot sauce on ice cream.” Blessing was killed by an improvised bomb in Asadabad, Afghanistan, in 2003.

“I mean, why did my friend get blown up? For what?” said Amenta, who has recently spoken to nearly six dozen veterans from the post-9/11 wars to write a book that will be released next month.

The Taliban captured Kandahar, Afghanistan's second largest city, on Aug. 13, as U.S. troops continue to withdraw from the region. (Reuters)

In the United Kingdom, which lost at least 455 troops over the course of the war, Foreign Affairs Select Committee Chair Tom Tugendhat, who served in Afghanistan, tweeted: “If you think I’m taking the news from Afghanistan badly and personally, you’re right.”

Tugendhat said the withdrawal was “wasteful and unnecessary.” He added, “I’ve seen what it costs and what sacrifices are being thrown away.”

Tugendhat, in a BBC interview, said that withdrawing coalition support in the country has left its government exposed and weak. “We’ve pulled the rug from under them,” he said. “We’ve taken away their air support, we’ve taken away their logistics, and we’ve said, ‘Go on then, let’s see how you do.’ ”

Speaking from his home in Tucson, Army veteran John Whalen sighed as reports came in that Kandahar, the second-largest Afghan city, had fallen to the Taliban.

“It’s just frustrating,” Whalen said over the phone. “We knew that this would happen. Now, all the people who went and served, are like, ‘Why did my friend die?’ ”

“I ask that question, too,” Whalen said.

Whalen said two of his friends were killed just a dozen miles from Kandahar in 2010: Andrew Meari of Plainfield, Ill., and Jonathan Curtis of Belmont, Mass.

The two were guarding an entry point at Combat Outpost Sanjaray. When they stopped a suspicious individual from entering the base, the individual detonated explosives he had wired on himself, the Associated Press reported.

“I like where I am right now. I’m doing good,” Whalen, now 34 and working as a cybersecurity consultant, told The Washington Post. “But they’re dead,” he said of his friends.

“He was just a kid,” Whalen said of Pfc. Meari, who was 21 when he died. “He was so motivated. He was just so excited to go out and live his life. But he got killed. And he didn’t get to live his life.” Curtis had an infant daughter at the time, Tessa-Marie.

“I’ve felt that there was this idea behind America. That America would make the world a better place,” he said. “But there are kids in Afghanistan that have only seen war during their lives,” said Whalen, who has a 7-year-old son, Oliver. It doesn’t feel right, he added.

Former Army medic Frank Scott Novak, 44, said he has repeatedly heard a lingering sense of sadness from military friends who served in Afghanistan as developments continue to unfold. Novak served two tours in Iraq from 2004 to 2006.

“No one’s saying, ‘Hey, you know, at least we did something.’ There’s just nothing to really show for it,” he said. “And so, everyone’s kind of angry and wondering, why? Why were we even there?”

Michelle Partington, the first woman to serve as a front-line Royal Air Force paramedic, told Britain’s Channel 4 that she finds it unbearable to watch the country’s fall.

Partington suffers from post-traumatic stress disorder following three deployments to Afghanistan, which she described as “a nightmare,” citing bomb blasts, injuries and widespread destruction. She told the broadcaster that upon her return from the country, she frequently considered taking her own life.

“My war is still ongoing,” she said, adding that she was unable to think about the present situation in Afghanistan “because it’ll take me back to my illness.”

Jeong Jangsoo, a retired South Korean army colonel, expressed a cocktail of emotions — none of them good — after learning Friday night on his way home in Seoul that the Taliban was nearing Kabul.

In Taliban militants’ biggest victories in their week-long surge, local officials told The Post on Friday, Afghan troops retreated from Kandahar, Herat and Lashkar Gah. Fighters are closing in on the national capital, heightening concern that the Afghan government will largely collapse and leave Kabul the last island under its control.

Jeong commanded an approximate 300-person South Korean contingent in Afghanistan in 2007, when the Taliban kidnapped a South Korean Christian group, ultimately killing two of its members.

“I felt disappointment,” he said in a phone interview, “a sense that all had been in vain, and thought, ‘So this is how it ends, huh?’ ”