The Supreme Court has agreed to take up the lawsuit over President Obama's 2014 executive actions on immigration, which would allow millions of unauthorized immigrants to apply for protection from deportation. The court will hear and decide on the case, United States v. Texas, by summer 2016. 26 states sued the federal government to stop the executive actions. A federal judge in Texas sided with the states in February 2015, and the Fifth Circuit upheld the ruling in November 2015. So far, the case has only been about whether the administration can start implementing the programs until the court makes a permanent decision. But now, the Supreme Court will be taking up the question directly: are the administration’s executive actions constitutional or not? The injunction affects two programs the Obama administration had been hoping to start in spring 2015. Both of them would allow groups of unauthorized immigrants to apply for protection for deportation and work permits. One program would cover immigrants older than 30 who came the US as children; the other would cover parents of US citizens and permanent residents.

The White House is looking to the Supreme Court to save its immigration legacy

In 2014, President Obama announced a series of executive actions on immigration, including two new programs to grant "deferred action" (protection from deportation) and work permits to unauthorized immigrants in the United States.

One program would protect unauthorized immigrants who'd come to the US as children but were now older than 30 (expanding a deferred-action program that's been around since 2012). The other would protect parents of US citizens and permanent residents who'd been in the US for at least 5 years. Taken together, the two would protect about 4 million unauthorized immigrants from deportation.

The executive actions were designed to be President Obama's legacy on immigration. He hadn't kept his campaign promise to push for immigration reform in Congress in his first term; Congress tried, and failed, to pass it in his second. The first several years of the Obama presidency were marked by record deportations of unauthorized immigrants, many of whom had lived in the US for years.

The only unqualified success the president had was his 2012 executive actions to protect young unauthorized immigrants who would have qualified for the DREAM Act from deportation; that's what he built on in 2014.

26 states sued the Obama administration to keep the programs from going into effect. In February 2015 (days before the administration was supposed to start accepting applications) a federal judge issued a preliminary injunction that prevented the administration from doing anything to implement the deferred-action programs.

The administration appealed the injunction to the Fifth Circuit Court of Appeals, which (in November) officially upheld the injunction against the administration — keeping the deferred-action programs on hold. Now, the Supreme Court has agreed to take up the case this term — which means it will be resolved while Obama is still in office, giving the president a chance to redeem a signature program.

This isn't about whether Obama's actions are constitutional — and it's not even a final ruling on them

The lower courts have not yet issued a final ruling on the Obama administration's programs. They've issued injunctions: meaning that while the courts haven't decided whether or not the president's executive actions are unconstitutional or illegal, the government has to stop acting on them while the courts makes up their mind.

The Supreme Court, on the other hand, has agreed to take up the whole thing at once. It's going to rule directly on whether the executive actions are constitutional, or whether Obama violated the "Take Care Clause" of the Constitution by attempting to protect immigrants who are deportable under federal law.

The heart of the legal dispute: Do agents really have discretion to reject immigrants' applications?

At the Supreme Court, it's generally assumed that the four liberal justices will side with the Obama administration, and it's entirely possible that swing vote Anthony Kennedy will side with them too. Supporters of the Obama administration are looking to the dissent in the Fifth Circuit case — written by the Democratic appointee on the panel — for a model of what they hope the Supreme Court decision will look like.

The dissent is a pretty straightforward defense of the deferred-action programs. It focuses on what the memo creating the deferred-action program says the program would do, while the majority (as well as Judge Hanen in his earlier ruling) focused on other evidence to predict whether the new programs would work that way in practice.

This is the heart of the legal dispute. Are the new deferred action programs actually discretionary? Or do they force agents to follow hard-and-fast rules for approving applications, and any talk of "discretion" is just a legal fig leaf?

The court could issue a very narrow ruling or a very broad one

Like most of the highest-profile Supreme Court cases of the Obama administration, this case is expected to split the Supreme Court among ideological lines. The court's progressive wing — Justices Ruth Bader Ginsburg, Steven Breyer, Sonia Sotomayor, and Elena Kagan — is expected to side with the administration. Its conservative wing — Chief Justice John Roberts and Justices Antonin Scalia, Clarence Thomas, and Samuel Alito — is expected to side with the states. The "swing vote" on the court, Justice Anthony Kennedy, is expected to carry the decision one way or the other.

But in addition to the question of whether the Supreme Court will side with the Obama administration or with the states, there's the question of how broad the court's ruling will be. If the court does strike down the executive actions as unconstitutional, will it do the same for the existing deferred-action program from 2012, which covers hundreds of thousands of young immigrants?

Supporters of the states are hoping that the Supreme Court's decision will resemble the decisions issued by district judge Andrew Hanen, and by the two Fifth Circuit judges in the majority. (All three are Republican appointees.)

The initial injunction was pretty narrow, and focused on "procedural" grounds — whether the Obama administration was obligated to follow the process for submitting new regulations for public comment, as laid out in a law called the Administrative Procedures Act.

The administration argued that because the deferred-action programs were discretionary — individual agents could decide who to approve and who to reject — they weren't the type of regulation that needed to be submitted for public comment. Judge Hanen, and the Fifth Circuit, disagreed. The courts have ruled that in practice, agents wouldn't be allowed to reject any deferred-action applicants who met the criteria Homeland Security Secretary Jeh Johnson had laid out, so it wasn't really discretionary at all.

But the Fifth Circuit's ruling in November went further than the initial ruling in district court. According to Cecilia Wang, Director of the Immigrant Rights Project for the ACLU, the district court ruling said that "if (the government) wanted to do these things it should have provided notice in the Federal Register, with period for comment." But the Fifth Circuit ruled that even if the administration had followed the procedure for issuing new regulations, it still wouldn't have been legal, because the administration didn't have the authority to create the programs to begin with.

Because the Supreme Court has agreed to consider the question of constitutionality directly, it could go even further than the Fifth Circuit has. But it could also issue a narrow ruling that split the difference between the two sides: finding that the executive actions were constitutional, but that the administration should have followed the regulatory process to make them.

The lawsuit doesn't cover immigrants who've already gotten deferred action

Immigrants who are currently under 30, and who came to the US as children are teenagers, are still able to apply for deferred action. That's because the lawsuit isn't challenging the original Deferred Action for Childhood Arrivals program that was implemented in 2012.

The lawsuit did, however, challenge a change the Obama administration made to the program in 2014: extending deferred action from a two-year grant of protection to a three-year grant. Immigrants who had gotten approved for three years of deferred action had to return their documents or risk getting tracked down by the government.

Because states aren't suing to end the original DACA program, the Supreme Court doesn't have to address whether it was also illegal for the same reasons the 2014 programs are. But if it feels particularly strongly that the executive actions are unconstitutional, it might strike down the DACA program as well.

Most of the arguments that lower courts have used against the 2014 programs could also apply to the existing DACA program. In fact, most of the evidence the courts have used to show that deferred action isn't really discretionary is information about how the current deferred-action program is being applied.

The dragged-out court case might have already damaged the policy

Ever since the initial ruling came down in February, the federal government hasn't been able to do anything to implement either of the new programs President Obama announced in November to protect unauthorized immigrants from deportation.

Between the two programs, millions of immigrants were supposed to be eligible for deferred action (three years of protection from deportation) and work permits. Neither of those programs had actually started accepting applications yet, although one was supposed to start days before the initial injunction was issued in February. Now they won't be able to start until further notice.

Immigrants who are older than 30 but who came to the US as children or teenagers (and meet other requirements) were supposed to be able to apply for deferred action starting on February 18. That's about 290,000 immigrants who'll remain vulnerable to deportation.

There are also the 3.7 million unauthorized immigrants who are parents of US citizens or permanent residents who'd benefit from the second program, for which applications were supposed to open in the spring.

At this point, the two programs have been on hold for 9 months. President Obama will only be in office for 14 more months. Even if this ruling is (somehow) quickly overturned, and the administration is allowed to move forward with granting deferred action, the success of the relief programs might be in jeopardy.

When the administration created the first deferred-action program in 2012, for young unauthorized immigrants, they discovered the success of the program relied on people signing up — and on the ground, organizers learned that finding eligible immigrants and getting them to apply was the hardest part. Now, community groups are trying to educate a much larger, more diffuse immigrant population about the new deferred-action programs, and persuade them that it's safe to apply. But news and misinformation about the lawsuit is spreading confusion and fear among the very people these groups are trying to reach.

Organizers are worried about a "chilling effect": by the time applications do open for deferred action, immigrants will have been intimidated out of applying, because they won't believe the program is safe or permanent.

What are the states suing the administration?

Twenty six states have joined the lawsuit. (Most are suing directly as the state, via the attorney general; in a few cases where the attorney general is a Democrat but the governor is a Republican, the governor joined the lawsuit on his own.) On the other hand, 13 states filed a brief siding with the federal government and urging the judge to let the actions stand. Here's the breakdown:

Of course, since Republican states are (by and large) less diverse than Democratic ones, this means that the states suing the Obama administration over immigration aren't the states with the most immigrants. In total, the states suing the president have about 2 million unauthorized immigrants who could benefit from deferred action, or about 38 percent of all immigrants who could benefit (according to the Migration Policy Institute). Without Texas, that drops to 24 percent. The 13 states (plus the District of Columbia) siding with the administration have 2.6 million potentially eligible immigrants — half of all immigrants who could benefit.

And in addition to the states that have sided with the federal government, 30 cities have filed on Obama's side as well — including some cities in states that are on the opposite side of the suit, like Houston.

How can states even sue to stop the federal government over this?

This is actually part of the lawsuit itself. The federal government is arguing that the states don't even have the authority (called "standing") to bring this lawsuit into court at all — because they can't show that the state governments themselves are being harmed by immigrants getting deferred action.

The states are arguing that they have to "bear the burden" of unauthorized migration by paying for public schooling for unauthorized immigrant children; including US citizen children whose parents are unauthorized in safety-net programs; and especially, by having to provide "uncompensated" emergency care to unauthorized immigrants who don't have health insurance, since they're barred from participating in the exchanges under Obamacare and don't have low-cost insurance options. Furthermore, they claim, Obama's executive actions will encourage more unauthorized immigrants to come to the US, which will burden the states even more.

The courts haven't bothered to address most of these claims. Instead, they say the states have standing because Texas — one of the 26 states — would have to spend millions of dollars on drivers' licenses for deferred-action recipients.