(CBS News) — Former President Obama condemned the Trump administration’s “cruel” decision to rescind one of his signature policies, that enabled undocumented immigrants brought to the U.S. as children to remain here with temporary permits.

To target these young people is wrong – because they have done nothing wrong,” the former president wrote in a Facebook post. “It is self-defeating – because they want to start new businesses, staff our labs, serve in our military, and otherwise contribute to the country we love. And it is cruel. What if our kid’s science teacher, or our friendly neighbor turns out to be a Dreamer? Where are we supposed to send her? To a country she doesn’t know or remember, with a language she may not even speak?

He added, “Let’s be clear: the action taken today isn’t required legally. It’s a political decision, and a moral question. Whatever concerns or complaints Americans may have about immigration in general, we shouldn’t threaten the future of this group of young people who are here through no fault of their own, who pose no threat, who are not taking away anything from the rest of us.”

Mr. Obama, who implemented Deferred Action on Childhood Arrivals (DACA) in 2012, said when he left office he would comment on Mr. Trump’s actions at “certain moments where I think our core values may be at stake.”

Among the issues that would cause Mr. Obama to speak out, he strongly implied at the time, was DACA or, as he put it, “efforts to round up kids who have grown up here, and for all practical purposes are American kids, and send them someplace else, when they love this country.”

Mr. Obama’s executive order defers deportations for people who came to the U.S. undocumented as children. Almost 800,000 people are in the U.S. now because of it.