The protestors say those flags represent 39,000 non-citizens currently serving in the U.S. military.
The group says Memorial Day is about honoring those who made this country what it is. But they say that's not possible for many families. They claim that each day 1,100 families are separated by deportations.
"We want him to realize that there are thousands of soldiers out there fighting for American values, family unity being one of them. And yet our current laws do not respect family unity and instead separate mothers from children, fathers from wives," said Cindy Agustin, University of Chicago student.
The group began their vigil Sunday night. It was organized by the Illinois Coalition for Immigrant and Refugee Rights.