I would add that the part of the president’s new policy offering work permits to some of those whose deportation is deferred in no way changes the analysis above. The work permits are merely a formalization of the president’s exercise of prosecutorial discretion here, which indicates that the administration will not attempt to deport these people merely for being present in the United States and attempting to find jobs here. They do not purport to legalize their status, and the policy of nondeportation can be reversed at any time by the president or his successor.
That seems to me to be stretching the word “discretion.” “Discretion,” in the prosecutorial context, means that we recognize that law-enforcement officials are not necessarily obliged to act in every case; which is to say, the discretion they have is the discretion to not act. It is not the discretion to confer legal rights and privileges upon people who are not entitled to them, e.g. to offer them work permits to which they are not entitled. This isn’t a case of the Obama administration’s not acting, but a case of not not acting, the equivalent of making a declaration that every mass shooter charged with killing fewer than three people not only is safe from federal prosecution but also will be awarded $1,000 a month in federal welfare payments regardless of eligibility, or that they will all be admitted to national parks for free for the rest of their lives.
The word “discretion” is related to the word “discrete,” meaning distinct, separate, and particular — the opposite of general, categorical, and universal, which is the scope at which the president here purports to operate. The power to exercise discretion in the enforcement of one law is not the power to exnihilate another law into existence. That this should be so thoroughly obfuscated seems to me another piece of evidence that the corruption of the English language is the main project of the legal profession.