Why are Idaho, Maine, and Nebraska suing over Obama's immigration plan?

Well, that didn’t take long.

A coalition of 20 states filed a lawsuit to try to block President Obama’s recent immigration policy changes, which could shield up to 5 million people from deportation.

Texas Gov.-elect Greg Abbott (R), who is leading the charge, said Obama is “abdicating his responsibility to faithfully enforce laws.”

Here’s what you need to know about the lawsuit.

1. The legal argument centers around the “Take Care” clause of the U.S. Constitution. As The Wall Street Journal points out, the name sounds like “a friendly send-off,” but the take care clause actually references Article II, Section 3 of the Constitution, which lists the president’s duties. “He shall take care that the laws be faithfully executed” is one of those duties. The states are arguing he isn’t doing it.

2. The White House was prepared for this. When the president rolled out his plan, he also released the legal argument defending it. The Justice Department’s Office of Legal Counsel released a 33-page memorandum spelling out why the administration had the power to unilaterally grant deportation relief. The memo explains that while the president should faithfully execute the laws, there’s still room for discretion, something the Supreme Court recognized in the 1985 case Heckler v. Chaney.

3. Most states suing over immigration have few immigrants. Of the 17 states that initially filed suit against the federal government —Alabama, Georgia, Idaho, Indiana, Kansas, Louisiana, Maine, Mississippi, Montana, Nebraska, North Carolina, South Carolina, South Dakota, Texas, Utah, West Virginia and Wisconsin—Texas was the only one where foreign-born residents made up more than 10 percent of the population (the national average is 13 percent). The other states involved in the lawsuit have much smaller immigrant populations than places such as California, New York or New Jersey. On Thursday, however, Arizona and Florida — two big immigration receiving states — joined the lawsuit, along with Ohio.

4. A similar lawsuit failed in 2013. This isn’t the first time Obama has granted deportation relief: he announced a program in 2012 that would allow more than a million young undocumented immigrants to live and work in the U.S.

Immigration hardliners were fuming then, too. Chief among them was Kansas Secretary of State Kris Kobach, who filed a lawsuit on behalf of a group of federal immigration agents, arguing that the policy change prohibited them from doing their job. Kobach also cited the “take care” clause of the Constitution.

Beyond that, the Supreme Court has already ruled in a relevant case: the 2012 decision tied to Arizona’s immigration law, SB 1070. In the majority opinion, Justice Anthony Kennedy wrote about the president’s discretion to enforce the law. “A principal feature of the removal system is the broad discretion exercised by immigration officials,” he stated. “Federal officials, as an initial matter, must decide whether it makes sense to pursue removal at all.”

The U.S. district judge hearing the case ultimately decided that it was not within his jurisdiction to rule on the issue, since this was a dispute between federal employees and the U.S. government. But in his opinion, he noted that he would have ruled in favor of the plaintiffs if the case had been within his purview.

5. Immigrant rights groups are backing Obama. For the past year, organizations have challenged the president to take action. He did it — and now they’re supporting him. The pro-immigration reform outfit America’s Voice held a press call with legal experts on Friday to pick apart the lawsuit against Obama’s immigration plan, with one participant calling it “press release” material. The more radical Latino-rights organization Presente.org responded less diplomatically with a statement from Executive Director Arturo Carmona. “Republicans will pay the price for treating Latino families like trash,” he said.

Update, Dec. 6, 12:15 p.m.: This post was updated to include the addition of three states, Arizona, Florida and Ohio, to the list of those suing the federal government over immigration enforcement.

Ted Hesson was formerly the immigration editor at Fusion, covering the issue from Washington, D.C. He also writes about drug laws and (occasionally) baseball. On the side: guitars, urban biking, and fiction.