The quote in the title is the full text of 6 U.S.C. § 202(5).
Executive discretion– the most familiar example being prosecutorial discretion– is a bedrock concept of our law. The executive cannot pursue every case, and so they have the authority, often explicitly granted by statute, to select what cases to pursue. It is not just legal but a good thing that this discretion can be exercised case-by-case (deciding whether individual cases warrant prosecution, for instance) or through policy (deciding which cases most warrant prosecution resources and which ones, as a matter of policy, do not). Immigration law is an area where Congress has explicitly granted the President the authority to make these sorts of choices, including at the level of having policies about which cases to pursue deportation and which cases to not pursue deportation. Congress has explicitly provided principles for that exercise that provides that the policies should favor deportation of criminals, national security threats, and the like, over people who are merely working here.
And that has what the President has done. I have three essential readings on the subject. One is from Eric Posner, a law professor at the University of Chicago who served as a lawyer in the most recent Bush administration. The other is from Walter Dellinger, who served as the director of the Office of Legal Counsel from 1993-1996. Both say it is crystal clear that this is legal. The third is the actual opinion by Justice Department lawyers about what sort of discretionary policies would be legal and, in one instance, what would not.
Congress could legislate away or limit the discretion it has explicitly granted, but won’t because it would still present a problem– Congress is only funding resources to deport about 400,000 a year, and so somehow and someway, discretion is going to be exercised in selecting who those 400,000 might be. Surely allocation of resources by a plan would be better than essentially saying “Pick up the first 400,000 undocumented folks you get your hands upon.”
There are demagogues out there screaming for impeachment, which is ludicrous given the clear law here. The more lunatic even scream for criminal prosecution and jail– one tweet seemed to think that the “maximum punishment” could proceed after impeachment, evincing a failure to understand that part of the constitution, too (the term for what happens after impeachment is “removal”– or not– and not punishment). This is a demographic that seems particularly impervious to evidence-based analysis, but what can we do?