Federal courts have a limited geographic jurisdiction. Traditionally, when you wanted to make a nationwide challenge to a government action, you would bring the case in the D.C. Circuit. A decision against an agency by a court that had jurisdiction over its headquarters would have a nationwide effect.
This process had gone out the window in the age of Trump. Groups challenging Trump’s actions fan out across the country and file the same lawsuit in multiple courts in the hope of finding a judge who will not only side with them, but issue a nationwide injunction that exceeds the geographic limits of the court’s power.
In the case of the public-charge rule, two lawsuits were brought within the Ninth Circuit, one of which resulted in a nationwide preliminary injunction again the rule. However, the Ninth Circuit issued a stay of the injunction, allowing the rule to go into effect while the litigation progresses.
Another lawsuit was brought in Maryland, where the judge granted a nationwide injunction. The Fourth Circuit granted the government a stay of the injunction, allowing the rule to go into effect while the litigation progresses.
Another lawsuit was brought in New York, where the district court granted a nationwide injunction. The Second Circuit refused to stay this injunction.
Still another lawsuit was filed in Illinois. However, the Illinois district court limited its injunction to that state. An appeal of that decision was filed.
On the question of whether a preliminary injunction was proper, the government has won two out of three. Under this growing practice of nationwide injunctions, the government could win 10 out of 11 and still lose.
The Supreme Court stayed the New York injunction, but left the Illinois injunction in place. The effect of the various courts so far is that all the nationwide injunctions have been stayed and the one injunction limited to its geographic jurisdiction (Illinois) remains in place.
In the Ninth Circuit, Judge Jay Bybee, "concurring, perplexed and perturbed" in the decision, wrote:
By constitutional design, the branch that is qualified to establish immigration policy and check any excesses in the implementation of that policy is Congress. And, so far as we can tell from our modest perch in the Ninth Circuit, Congress is no place to be found in these debates. We have seen case after case come through our courts, serious and earnest efforts, even as they are controversial, to address the nation's immigration challenges. Yet we have seen little engagement and no actual legislation from Congress. It matters not to me as a judge whether Congress embraces or disapproves of the administration's actions, but it is time for a feckless Congress to come to the table and grapple with these issues. Don't leave the table and expect us to clean up.
The Supreme Court's order has no bearing on whether the public-charge rule is lawful. However, it does indicate that the practice of fanning out to courts across the country in the hope of a single nationwide injunction is going to be neutralized.