FOR THE third straight year, the Supreme Court will ask whether Barack Obama overstepped his executive authority under the constitution. In 2014, the justices slapped Mr Obama on the wrist for taking liberties in making unilateral appointments to federal agencies while the Senate (which is supposed to give its “advice and consent”) was in session. Last year, they evened the score, siding with the White House in a tussle with Congress over who gets to recognise foreign governments. This spring, Mr Obama’s controversial moves with regard to immigration face a major challenge at the nation’s highest court. The Supreme Court agreed on January 19th to review lower-court decisions blocking the president’s actions to make life easier for nearly 5m illegal immigrants. A year away from his departure from the Oval Office, Mr Obama now has one more chance to persuade a court to give his immigration policy the green light.

At issue are a handful of executive orders announced in November 2014. The most consequential move enabled individuals whose children are citizens or lawful permanent residents to find relief from the immediate threat of deportation under a programme known as Deferred Action for Parents of Americans and Lawful Permanent Residents (DAPA). Another order expanded eligibility under Deferred Action for Childhood Arrivals (DACA), a policy designed to give children coming to America without papers a renewable, two-year reprieve from deportation. While both DAPA and DACA confer temporary protection against removal from the country and allow illegals to work, neither serves as a path to citizenship. The latter policy goal, advocated by each of the contenders for the Democratic presidential nomination, would require congressional approval.

In a Supreme Court term where voting rights, labour unions, affirmative action, Obamacare and abortion are already electrifying the docket, United States v Texas may be the most talked-about case in the presidential campaign that will be in full swing in late June when a decision comes down. The oral argument will take place in April. In contrast to the promises for immigration reform coming from Hillary Clinton and Bernie Sanders, Republicans are outdoing themselves to get tough on illegals, with the most muscular position coming from Donald Trump, who wants to build a wall across the southern border and send the bill to Mexico. All of the major GOP candidates oppose Mr Obama’s executive orders.

Hemmed in by a legal battle waged by Texas and 25 other states, the DAPA and expanded DACA programmes have yet to take effect 14 months after Mr Obama announced them. The White House pinned its hopes on prospects that the Supreme Court would agree to revisit a November ruling from the Fifth Circuit Court of Appeals declaring the actions illegal. Now that it has, the question turns on three legal issues.

First is the question of whether Texas and its fellow disgruntled states are even entitled to sue the federal government on an issue that is, by all accounts, a federal concern. The states have “standing”, two Fifth Circuit Court judges held, because they are on the hook to pay for subsidised driver’s licences for the individuals protected under DAPA and DACA. They are therefore harmed by the executive actions and have cause to sue. But the dissenting judge in that 2-1 ruling, Carolyn King, expressed grave doubts on the standing question. If a state could sue any time a federal rule costs them some money, the courts might be very busy indeed.

The second question has to due with the Administrative Procedure Act (APA), a law requiring that policy changes go through a formal policy of “notice-and-comment” before they take effect. Mr Obama’s immigration changes, the states charge, did not fit this bill. But Nicholas Bagley, a University of Michigan law professor, notes that public vetting of the executive orders was at least as extensive as what the APA demands. “[T]he administration supplied notice in a much more effective manner: it leaked the proposal to the national media and held a Rose Garden press conference. The administration also didn’t respond to comments, point by point, in a document titled ‘Final Rule.’ But it did address, in writing, the most substantial objections to the program.” The administrative rules, Mr Bagley writes, “[don’t] demand anything more rigorous than that”.

The justices took it upon themselves to add a third question to their deliberations in United States v Texas: “whether the guidance violates the Take Care Clause of the Constitution, Article II, section 3”. This is the constitutional provision requiring the president to “take care that the laws be faithfully executed”. Texas and its fellow litigants argue that Mr Obama abrogated this role and made up his own immigration rules, violating the constitutional separation of powers. The White House insists that the secretary of homeland security, the official directly responsible for issuing the changes, has wide discretion to decide by what principles it will spend its limited funds to go after illegal immigrants and return them to their home countries. Only 4% of the 11m “removable aliens” can be deported in a given year. Deferring deportation for certain segments of the illegal population “encourage[s] these people to come out of the shadows, submit to background checks, pay fees, apply for work authorisation…and be counted”, they argue.

If the Supreme Court sides with the administration, undocumented migrants who are eligible to apply for deferred action may still have reason to be wary. A Republican win in the November presidential election may well herald the evaporation of the new protections come January 2017. Notifying the authorities of one’s presence on American soil in exchange for, at best, six months of peace of mind may be a dodgy bet in a political environment in which immigration policy could soon be up for another upheaval.