If you need–and who doesn’t?–a basic layman’s guide to the basic legal issues surrounding the president’s expected executive action on immigration, Greg Sargent does it up with considerable efficiency today. Here’s one of two really important points that have been missed by a lot of people:

It has long been a basic reality of immigration law that the federal government only attempts to remove a small fraction of the country’s undocumented population. That’s true today. As Julia Preston observes: “Congress has provided only enough funding for the administration to carry out about 400,000 deportations each year. Mr. Obama, to the dismay of immigrant-rights advocates, has met that goal.” That is a small fraction of the 11 million undocumented immigrants. The question is: How should the enforcement bureaucracy choose who belongs to that small fraction, and how far can he go in setting down guidelines for determining that?

So the answer to those who ask why Obama just doesn’t “enforce the law” is that “enforcing the law” is very expensive, and Congress hasn’t given him–or any other recent president–remotely anything like the resources to do that. This is exactly why I argued earlier today that opponents of the executive action who want to keep the law more or less as it is–or even make it tougher–have a responsibility to explain exactly how it is the administration is supposed to deport millions of people. Without the resources and the strategy to “enforce the law,” the argument is really between those in the administration who want to set clear priorities on how to use limited enforcement resources and those elsewhere who for whatever reason (encouragement to self-deportation?) want to keep it murky.

Greg makes another important point about the alleged audacity of Obama’s DACA action and its impending successor:

[U]nder George H.W. Bush, some 1.5 million people were granted deferred action status by category — they were family members living with an immigrant in process of legalizing — and this included work authorization.

So while Obama’s executive action may unique in scale, it’s not unprecedented, and he’s relying on the same statutory authorizations for taking it as did his predecessor. And remember this: so long as the number of people still being prosecuted and deported is at the maximum levels funded by Congress, this really just is a clarification of prosecutorial intent, and won’t diminish the soul-satisfying-to-conservatives spectacle of people being thrown back over the borders.

Ed Kilgore

Ed Kilgore is a political columnist for New York and managing editor at the Democratic Strategist website. He was a contributing writer at the Washington Monthly from January 2012 until November 2015, and was the principal contributor to the Political Animal blog.