Sen. Bernie Sanders on Sunday said if Congress fails to come up with a solution for young immigrants known as “Dreamers” deporting them would be “one of the ugliest stains” in US history.

“If we allow Trump to get away with what he did and that is repeal the executive order on DACA, and if these 800,000 people, young people, are subjected to deportation, this will be one of the ugliest stains in the history of the United States,” the Vermont independent said on CNN’s “State of the Union.”

Democrats have said any deal to fund the government must include a solution for the Deferred Action for Childhood Arrivals, which protects from deportation immigrants brought illegally to America as children by their parents.

Last September, Trump rescinded the 2012 program created by former President Obama and gave Congress six months to come up with a legislative fix. That deadline is March 5.

The Senate failed to reach a vote on the temporary spending plan on Friday.

Sanders, who ran for president in 2016, said if the “Dreamers” are deported, America will “never recover. ”

“Young people who know no other country than this country, who came here at 2 or 3 years of age, to now be subjected to deportation would be a stain that this country would never recover from,” he said.