In his statement, Obama did not mention President Donald Trump by name but made clear that he disagrees with the administration's decision to end DACA, which protects young people who were brought to the United States illegally as children from being deported.
Many expected Obama to issue a response to the decision, since at the final press conference of his presidency, on Jan. 18, he pledged he would speak out about any action taken against Dreamers, as DACA enrollees are sometimes known.
Obama started his statement today by saying that while people can disagree about how to have an immigration system in which "everybody plays by the rules," that is not what Trump's decision to end DACA is about.
"This is about young people who grew up in America — kids who study in our schools, young adults who are starting careers, patriots who pledge allegiance to our flag. These Dreamers are Americans in their hearts, in their minds, in every single way but one: on paper," Obama wrote.
He also said that while considering what to do with Dreamers during his presidency, he asked Congress to send him a bill that would help address their future, but "that bill never came."
"Because it made no sense to expel talented, driven, patriotic young people from the only country they know solely because of the actions of their parents, my administration acted to lift the shadow of deportation from these young people, so that they could continue to contribute to our communities and our country," he wrote.
"We did so based on the well-established legal principle of prosecutorial discretion, deployed by Democratic and Republican presidents alike, because our immigration enforcement agencies have limited resources and it makes sense to focus those resources on those who come illegally to this country to do us harm," Obama continued.
"To target these young people is wrong — because they have done nothing wrong. 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," he wrote.
Obama took aim at the decision, which the Trump administration said needed to be made by today because of lawsuits that were set to be filed against DACA.
"Let's be clear: The action taken today isn't required legally. It's a political decision and a moral question," Obama wrote.
"Ultimately, this is about basic decency. This is about whether we are a people who kick hopeful young strivers out of America or whether we treat them the way we'd want our own kids to be treated. It's about who we are as a people — and who we want to be," he wrote.
During his final news conference before leaving office, Obama cited an attack on DACA as a possible situation "where I think our core values may be at stake."
Former Vice President Joe Biden was the first member of the Obama administration to speak out after the Sessions announcement, sharing a statement on Twitter earlier today.
"Brought by parents, these children had no choice in coming here. Now they'll be sent to countries they've never known. Cruel. Not America," Biden wrote.