In a dissent in Arizona v. United States, decided in June 2012, Justice Antonin Scalia offered an indignant and scalding rebuttal to the Obama administration’s assertion of broad federal power over immigration policy. He rejected the majority’s warning that if the Arizona law were left to stand entirely, every state could take over the federal job of prosecuting immigration violations. He accused the Obama administration of wholesale failure to enforce the law.

But there has come to pass, and is with us today, the specter that Arizona and the states that support it predicted: A federal government that does not want to enforce the immigration laws as written, and leaves the states’ borders unprotected against immigrants whom those laws would exclude.

Justice Scalia also took the unusual step of raising an issue that had not been part of the case, assailing President Obama’s executive program granting protection from deportation to young undocumented immigrants, citing it as evidence of the administration’s abdication.

But to say, as the court does, that Arizona contradicts federal law by enforcing applications of the Immigration Act that the president declines to enforce boggles the mind.

Painting a vivid — and controversial — picture of mayhem he said was caused by illegal immigration, he concluded that the majority’s ruling, written by Justice Anthony Kennedy, had undermined the basic rights of the states.

Arizona’s citizens, he wrote,

feel themselves under siege by large numbers of illegal immigrants who invade their property, strain their social services and even place their lives in jeopardy. … The laws under challenge here do not extend or revise federal immigration restrictions, but merely enforce those restrictions more effectively. If securing its territory in this fashion is not within the power of Arizona, we should cease referring to it as a sovereign state. I dissent.

Justice Scalia’s criticism of the program for young immigrants previewed his likely opinion in a case currently before the court: the challenge by Texas and other states to Mr. Obama’s executive actions in 2014 to expand that program and grant new protections to more than four million undocumented immigrants.

Now the outcome of the Texas case, deciding the future of an initiative Mr. Obama hoped would be a major part of his legacy, is even more uncertain, raising the prospect of a tie that could leave in place an existing injunction on the program, said Thomas Saenz, president of the Mexican American Legal Defense and Educational Fund, which is representing several immigrants in the case.

“It puts an even higher premium on the outcome of the presidential race in November,” Mr. Saenz said.

Correction: An earlier version of this post misstated the year in which President Obama took executive action to expand protections for undocumented immigrants. It was in 2014, not 2015.