Okay, you asked for it!
To me, the TRO’s validity mainly turns on two things:
(1) whether the TRO is even appealable (usually they’re not, but there are exceptions), and
(2) if so, whether the ACLU can show a likelihood of prevailing on its claims (a key element for obtaining TROs and preliminary injunctions).
_Aside__: You may wonder about the difference between a TRO and a “preliminary injunction.” A court will issue a preliminary injunction to preserve the status quo until a case can be finally decided. A TRO is like a short-term emergency preliminary injunction, intended to keep things at a standstill for up to 14 days so the court has a chance to make an informed decision about whether a preliminary injunction is appropriate. In short, the court normally decides first whether a TRO is warranted; and if so, then whether to replace the TRO with a preliminary injunction after 14 days; and if so, whether to replace the preliminary injunction with a permanent injunction at the end of the case._
Anyway, although preliminary injunctions are immediately appealable because they can last for a long time (until they’re dissolved or replaced with a permanent injunction), TROs are different. They’re so fleeting—normally 14 days in duration—that appellate courts normally won’t mess with them. They disappear before the appeal concludes.
But there are exceptions, and the AG has asserted some. I won’t bore you with the details, but her arguments are decent. I suspect that the DC Circuit will want to hear the appeal now, because otherwise they’re just going to see it again in a couple of weeks.
So let’s assume that the AG persuades the DC Circuit to decide the case. Then we turn to the merits. The ACLU bears the burden of showing some reasonable likelihood that it will prevail on a final judgment. I think that this question will center on how much authority Judge Boasberg has to second-guess the President’s actions under the Alien Enemies Act. The AG says he has virtually no authority; the ACLU naturally disagrees.
If the AG prevails on these questions, then Judge Boasberg’s TRO will likely be vacated and a preliminary injunction will become highly unlikely. I won’t try to guess the DC Circuit’s decision because I’m not familiar with the law—and as we’ve seen over the last four years, courts have proved to be unpredictable on all these new questions that are emerging.
But don’t forget: The TRO expires after 14 days no matter how you slice it. The real practical question is whether the courts will try to impose a more long-term injunction.
The extraordinary turbo class-certification order will also be in play, but I don’t expect it to play a key role right now. And there’s always the looming question whether Judge Boasberg has the power to issue universal injunctions. I expect that to get some attention, but maybe not until later, and not unless he issues an actual preliminary or permanent injunction.