This Monday marked the 18th anniversary of U.S. troops’ arrival in Afghanistan after 9/11. I deployed there a decade later.

As Marines, we rarely discussed why we were there, except for being hell-bent on taking the fight to the Taliban, which we did. And militarily, we won, disrupting enemy supply routes and daring them to come out and fight. Outgunned, they resorted to planting IEDs on trails and roads, sniping at us from a distance, or using explosive-laden vehicles.

But we didn't win in every sense of the word. For example, we'd capture bomb makers and hold them the maximum time allowed before being forced by the rules of engagement to give them to the Afghan Police, who would promptly release them back into the population to make more bombs to kill Marines. Whether it was family connections, local influence, or “missing” evidence, the corruption involved in this process was obvious.

After catching the same bomb makers over and over, we couldn’t tell who our real friends were. The Afghan national government might have claimed to be with us, but the local police — many with familial ties to the Taliban — and the Afghan National Army often didn’t get the memo.

During my second deployment, the Taliban started forcing children to plant bombs, with the unavoidable result required to stop American deaths: children sometimes died at the hands of U.S. forces, at the cost of our own seared consciences.

But the assault on American troops’ morality didn’t end there. We were also required to work alongside “allied” police chiefs whose tribal culture allowed them to “own” boys as young as eight, whom they dressed as females and forcibly, repeatedly, sodomized.

We were strictly forbidden to intervene. Don't believe me? Believe the New York Times:

“Former Special Forces officer, Capt. Dan Quinn, who beat up an Afghan commander for keeping a boy chained to his bed as a sex slave, said…he was relieved of command as a result...’We were putting people into power who did things worse than the Taliban,’ said Quinn… SFC Charles Martland, a highly decorated Green Beret, was forced out of the military after beating up an Afghan local police commander who was a child rapist. Martland became incensed after the Afghan commander abducted the boy, raped him, then beat up the boy’s mother when she tried to rescue him.”

The payback came when one of these boys — seeing us as allies of his rapist slave master — murdered three Marines. One of those Marines’ fathers told the Times, “As far as the young boys are concerned, the Marines are allowing (child rape) to happen, so they’re guilty by association. They don’t know our Marines are sick to their stomachs.”

I certainly was. I don’t speak lightly of these and other tragedies I witnessed.

Yet today, eight years after leaving Afghanistan, the region where I served has returned to Taliban control. And the questions remain: What is our end goal there? What’s our definition of victory?

Our military objectives were achieved long ago: al Qaeda in Afghanistan is defeated. Bin Laden is dead.

But given the glaringly obvious futility of expecting U.S. troops to “democratize” or “westernize” Afghani culture and morality, do politicians in Washington intend to keep American troops there forever?

I've joined other Afghanistan veterans at BringOurTroopsHome.US, and you can help by signing our petition. It’s time we stop deploying American troops to places where it's not just their lives and limbs that are at risk, but also their mental health and moral consciences, the scarred collateral casualties of endless wars propping up institutions that don’t reflect our values.

Ben Adams of Nampa, Idaho, is a student at Boise State University. He served in the U.S. Marine Corps from 2009 to 2014, including two tours in Afghanistan.