Although Mr. Obama is not breaking new ground by using executive powers to carve out a quasi-legal status for certain categories of unauthorized immigrants — the Republican Presidents Dwight D. Eisenhower, Ronald Reagan and George H. W. Bush all did so — his decision will affect as many as five million immigrants, far more than the actions of those presidents.
Mr. Obama’s action is also a far more extensive reshaping of the nation’s immigration system.
“The magnitude and the formality of it is arguably unprecedented,” said Peter J. Spiro, a Temple University law professor. “It’s fair to say that we have never seen anything quite like this before in terms of the scale.”
The breadth of Mr. Obama’s decision is already raising serious legal and constitutional questions, fueling Republican charges of imperial overreach and worries among some Democrats of future fallout.
In an acknowledgment of the difficult questions of law and executive power Mr. Obama is raising with his action, the White House took the unusual step Thursday night of releasing the formal, 33-page Justice Department memo detailing the action’s legal underpinnings. Such internal legal opinions are seldom revealed to the public.
The memo, White House officials and a broad array of legal experts assert that the president’s directive, announced Thursday night in a prime-time address to the nation, rests on firm legal ground.
As chief executive, they say, Mr. Obama has virtually unfettered “prosecutorial discretion” to decide when he will or will not prosecute criminal infractions.
They also say that because Congress does not appropriate nearly enough money to deport all of the 11 million undocumented immigrants estimated to be living in the United States, the president is obligated to choose whom he deports, so he cannot reasonably be accused of usurping lawmakers’ authority or failing to execute the law.
“The key is that the president’s actions will still leave millions of undocumented immigrants to go after, and that will be with resources appropriated by Congress that still make barely a dent in the remaining population,” said Stephen H. Legomsky, a Washington University law school professor who was chief counsel of the United States Citizenship and Immigration Services from 2011 to 2013.
The White House also released a letter Thursday night signed by 10 of the nation’s top legal and constitutional scholars, including Laurence H. Tribe of Harvard, a noted liberal, and Eric Posner of the University of Chicago, a conservative, that called the new policy “lawful” and “within the power of the executive branch.”
