The court fight over President Obama's plan to shield as many as 5 million immigrants from deportation involves a number of complex legal issues. U.S. District Judge Andrew S. Hanen in Texas issued an order late Monday at least temporarily blocking the program from going forward.
Here are answers to some frequently asked questions about the case and the ruling.
What would the administration's program do?
The program would "defer action" for a large class of immigrants currently in the country without legal authorization. They would not receive citizenship or legal status, but would not be at risk of deportation so long as the deferred action remained in effect. Under rules that have been in place for many years, immigrants with deferred-action status are also allowed to work legally in the U.S.
What legal authority does Obama claim for deferred action?
The government has had some form of deferred action since at least the 1960s. Executive branch officials have argued -- and courts have agreed -- that the president and the executive branch agencies that work under him have significant discretion over which immigrants to deport. The legal justification is that the government has limited resources and that federal agencies can set priorities.
"The decision to prosecute or not prosecute an individual is, with narrow exceptions, a decision that is left to the executive branch's discretion," Hanen agreed in his opinion Monday.
What's the legal argument on the other side?
Discretion isn't unlimited. The government can't completely rewrite the law under the guise of setting priorities. The legal issue is whether Obama's program is so big and far-reaching that it goes beyond what can be justified as executive discretion. The plaintiffs in the case before Hanen, 26 Republican-led states, have a strong case that the administration did go too far, the judge ruled.
The administration cannot "establish a blanket policy of non-enforcement that also awards legal presence and benefits to otherwise removable aliens," the judge wrote. The executive branch has "discretion in the manner in which it chooses to fulfill the expressed will of Congress" but cannot set up a program that "actively acts to thwart" what Congress intended, he wrote.
The Obama administration says the 26 states have no legal right to sue in this case. Why?
Federal courts only allow cases to proceed when the person or group bringing the case meets the legal standards for what is known as standing. To have standing, people or groups need to show several things, including that the action they want to challenge will have a direct, provable impact on them.
That rule is designed to prevent litigants from dragging courts into abstract disputes rather than what the Constitution limits them to considering, an actual "case or controversy." The administration argues that although Republican officials disapprove of Obama's decision, the states themselves will not suffer any actual injury.
What did the judge say?
Hanen ruled that the states would suffer an actual injury because the deferred-action program would cost them money. For example, states would probably be required to issue driver's licenses to immigrants with deferred-action status, he wrote. Because of that, the states have standing, the judge ruled.
Did the judge make a final ruling on the case?
No. Monday night's ruling said that the states could take their claim to a full trial, which might not take place for months. In the meantime, the judge issued an injunction blocking the administration from starting the new deferred-action programs.
"There will be no effective way of putting the toothpaste back in the tube" if the government starts granting immigrants deferred status, the judge wrote.
What happens now?
The government has said it will appeal. The case would go to the U.S. 5th Circuit Court of Appeals, which could decide to leave Hanen's preliminary injunction in place until the judges of that court can hold a hearing on the matter. The appeals court could also dissolve the injunction.
The judge said the administration may have failed to follow proper procedures in drawing up the new program. What's that about?
The federal government has a law, known as the Administrative Procedures Act, which lays out the steps that agencies must take when they issue new rules. Those typically include notice and an extended period for public comment, often between 18 months and two years. The states argue that the Department of Homeland Security should have been required to follow those procedures in setting up the deferred-action program. The administration says this is not the kind of program that is covered by those procedural requirements. Although the judge did not make a final ruling on that question, he clearly sympathized with the states' argument.