CHICAGO (CBS) — Veterans who returned their medals to NATO just over a week ago gathered at the Vietnam Veterans Memorial at on the Chicago River on Monday, to talk about their feelings on Memorial Day.

They are men and women who have been to war, but are now waging their own fight against war.

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Sabrina Waller, who served in the Kosovo conflict in 1999, threw her medals back last week – as anti-NATO demonstrators marched near McCormick Place during the NATO Summit.

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Standing with a group of veterans opposed to the war in Afghanistan, Waller asked that people remember the soldiers who have died fighting for their country.

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“Memorial Day is the day we remember their sacrifices. It should be the day that we ask why. Why they had to. Because the goal of our society and every society should be a world where such a sacrifice is not necessary,” she said.

Waller was joined by other members of the group Iraq Veterans Against The War. They also stood with members the group Vietnam Veterans Against The War, who held up a banner reading “Honor The Warrior – Not The War.”

The two groups called for immediate withdrawal of troops from Afghanistan, rather than waiting until the end of 2014, as the Obama administration plans.

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Waller has an 11-year-old son, and she said her goal is that her son never goes to war.