When the Supreme Court rules, in many instances it issues the final legal word on a particular issue. Congress can always try to legislate changes to the law after such a ruling, but as far as the judicial system is concerned, once the Supreme Court rules all lesser judges must follow their ruling. But this legal finality is not always true, because a Supreme Court ruling can, in many instances, only address one particular legal facet of the underlying constitutional case. The high court sometimes takes this route intentionally, ruling on one legal detail and then returning the case back to the lower courts for further proceedings -- allowing the initially-filed case to continue, just with new technical (and limited) instructions from the Supreme Court about how the lower judges should handle it. And although some saw the Supreme Court's recent decision on Donald Trump's executive order which attempted to redefine what birthright citizenship means in the Fourteenth Amendment as the final legal word, it was not. It wasn't even close to a final decision, since the Supreme Court actually completely ignored the underlying constitutional issue in question. Instead, they used the case to make a sweeping ruling limiting lower-court judges to issue nationwide injunctions which block some move by the president or his administration. By doing so, they overturned a nationwide injunction which barred the Trump administration from attempting to implement his new definition (which would have severely limited the grant of citizenship for babies born on American soil). But they put their order on a 30-day pause, and they left a loophole.

Today, that loophole was successfully used, and another lower-court federal judge issued a new block on the administration which will prevent them from beginning to implement their new policy anywhere in America. The judge did so by making the case a "class action," which certifies that any baby born anywhere in America is part of the "class" of plaintiffs suing to stop the administration's new move. In their technical ruling two weeks ago, the Supreme Court explicitly left open this legal route.

Many of the initial reactions to the Supreme Court's ruling took a "the sky is falling" attitude towards limiting lower-court judges to issue nationwide injunctions, but the loophole the high court left in their decision could in fact make their entire ruling rather limited in scope. This is clear for both the specifics of the birthright citizenship case and (in the larger sense) for nationwide injunctions in general.

The Supreme Court's order will make it harder for lower-court federal judges to issue any kind of ruling that applies nationwide. But it doesn't make it impossible, merely harder. To bring a class-action suit, you must first jump the legal hurdle of having your class approved. This is nowhere near as easy as having just a few plaintiffs file a lawsuit on their own, and it requires more legal technicalities to be met. But it is also not an insurmountable hurdle, as today's action shows.

Of course, since Donald Trump's motto for legal fights is: "appeal everything, all the way," today's ruling won't be the final word either -- even on just the question of whether such nationwide injunctions are still possible. The Justice Department will almost surely appeal the judge's ruling, which is a process that will play out over the next few weeks or months. And no matter what the appeals court rules, the issue is also almost certain to return to the Supreme Court. The high court will, no matter which way the appeals court rules, be essentially asked: "Is this what you meant? Is this still OK?" The high court could rule on the issue quickly (as a legal "emergency") or it could decide to take its sweet time and only accept the case in their regular docket (which would push any decision out many months).

Of course, with this Supreme Court, it's impossible to say how they will rule, whenever they get around to doing so. But there is good reason for optimism, since they explicitly left this loophole in their first ruling. They didn't have to do so -- they could have made their ruling even more sweeping. But they did. They carved out an exception for class-action cases, which makes plenty of legal sense since in many cases (just in general) the members of the class in question can be found all across the country. That's the whole point of class-action lawsuits: they bring together people who share one specific thing -- being harmed in some way by the people they are suing.

Even another Supreme Court ruling on the possibility of using class-action lawsuits to avoid their previous ruling limiting nationwide injunctions won't even begin to address the underlying constitutional case, however. This is the actual case being brought, instead of the legal technicalities about judicial rulings before the case is even heard. Both the individual plaintiffs and now the class in the class-action suit are suing to get the courts to declare Trump's interpretation of the Fourteenth Amendment unconstitutional. Which, on the face of it, it certainly seems to be. Trump has proposed a radical re-reading of the plain text in the amendment that has never been applied before, ever since the amendment was ratified (in 1868). He has no precedent to rely on. He is attempting to chart new legal territory -- even though the language of the amendment is pretty much clear as day. But that's a subject for an entirely different article -- I merely touch on it to point out that even with all this legal ping-ponging between lower-court justices and the Supreme Court, so far this underlying constitutional case hasn't been decided in a final way yet by anyone. When this does happen, the Supreme Court will be forced to directly deal with the constitutional argument, but for now we're off in the weeds of judicial powers rather than the definition of birthright citizenship itself.

But back to the practical effects of today's ruling and whatever the Supreme Court finally decides, just on the issue of nationwide injunctions. While liberals were aghast at the initial ruling two weeks ago, it will also apply in the other political direction. Joe Biden faced many lawsuits where the plaintiffs (or the money behind them) went "judge-shopping" to find the most conservative judge they could -- who then dutifully issued nationwide injunctions against all sorts of things. Including abortion access (the abortion pills case), as well as blocking many of Biden's executive actions. Once a Democrat is in the White House again, this legal tactic will resume from the right, without doubt. So the Supreme Court limiting such injunctions will eventually work in liberals' favor, at least in some cases.

Or maybe not. Maybe the entire thing will become no more than just a historical legal footnote. If the Supreme Court allows the new nationwide injunction in the birthright citizenship case to stand because it is now a class action (as they explicitly allowed for in their initial ruling), then we will have just shifted "the new normal" to add the hurdle of filing such suits as class actions. Judges will be able to accept the class status of plaintiffs no matter what their political bent (in liberal-supported cases and conservative-supported cases alike) and they will still have the power to issue nationwide injunctions to halt some action until the underlying case has a chance to be fully tried and adjudicated. That's not really all that big a change, since most of the cases where a president is testing constitutional limits involve large classes of people who will be affected.

The legal ping-ponging will continue. But the upshot might eventually be not that big a deal at all. We'll see. At the very least -- for now -- today's ruling shows that there still are options available to shut down unconstitutional moves by an overreaching president. For now, at least -- until the Supreme Court revisits their recent ruling, one way or the other.

-- Chris Weigant

Follow Chris on Twitter: @ChrisWeigant