You can find Justice Thomas’s opinion, dissenting from denial of cert. in two-Pennsylvania election cases, and Justice Alito’s separate dissent joined by Justice Gorsuch in the same cases, at this link beginning at page 25 of the pdf. The Court without noted dissent denied cert. in another PA case, the Kelly case. It takes four votes to agree to hear the case, and 5 to rule on the merits. There is no indication that Justice Barrett recused herself in consideration of the merits of these cases.

None of the dissenting Justices believed that these cases could somehow retroactively affect the outcome of the 2020 election. Indeed, they say it would not, but that the cases, while moot, should still have been heard because they present issues that will return to the federal courts. The main issue is the extent to which state courts, relying on state constitutions, may change rules for federal elections put in place by state legislatures. In the run-up to the 2020 elections, these three Justices, along with Justice Kavanaugh (who did not note a dissent in any of these cases today) expressed the view that the Constitution constrains the actions of state courts in such circumstances (viewing the legislature’s power as very broad).

This “independent state legislature” doctrine is a ticking time bomb, and it is an issue the Court is going to have to resolve, because these issues will return. As I explained back in November in a NY Times oped:

The worst appears yet to come. In one of the lawsuits that remains technically alive at the Supreme Court out of Pennsylvania, Mr. Trump and his allies have advanced a muscular version of something that’s become known as the “independent state legislature” doctrine. Taken to its extreme, the doctrine says that state legislatures have complete authority to set election rules absent congressional override, and that their power to set election rules cannot be overcome even by state supreme courts applying right-to-vote provisions in state constitutions.

That’s the basis for Mr. Trump’s claim in the U.S. Supreme Court that the Pennsylvania Supreme Court acted unconstitutionally in requiring the counting of mail-in ballots arriving up to three days after Election Day. (This is now a question for future elections because there are not enough ballots at stake to affect the 2020 count.) The doctrine also could be potentially violated by state and local election agencies even when they act under the Legislature’s authority to administer elections.

In the course of pre-election proceedings, Justices Samuel Alito, Neil Gorsuch, Brett Kavanaugh and Clarence Thomas issued or signed onto separate opinions endorsing the strong reading of this doctrine. The newest justice, Amy Coney Barrett, may well agree. And Chief Justice John Roberts, while not agreeing it was appropriate to apply this doctrine in these pre-election cases, was the lead dissenter in a 2015 case out of Arizona advancing a similar theory about broad legislative power to set the rules for federal elections.

Either in the Pennsylvania case or in another, the court’s conservative majority could soon embrace a strong version of the independent state legislature doctrine. This could take state courts out of their essential role in protecting voting rights. It could potentially eliminate the ability of voters to use ballot measures to enact nonpartisan redistricting reform and other measures that apply to federal elections. It could give conservative courts looking for an excuse a reason to scuttle voter-protective rules enacted by state election boards.

Together, the Trump-related precedents mean that neither state nor federal courts are likely to be able to play a backstop role when Republican state legislatures pass new restrictive voting laws, and that efforts to get around these state legislative efforts are likely to fail as well. Although in theory Congress has the power to override state legislatures with voter-protective legislation for federal elections, it is hard to see any of that getting through the next Congress even if Democrats barely grab control by winning the upcoming pair of Senate runoffs in Georgia.

So why didn’t the Court go further in this case? My guess is that it is either the fact that the case is moot (and the Court would rather address the issue in the context of a live case, but with lower stakes) or because the Trump cases are somewhat radioactive at the Court. Given former President Trump’s continued false statements that the election was stolen, the case would become a further vehicle to argue that the election results were illegitimate. It would thrust the Court back in the spotlight on an issue the Justices showed repeatedly they wanted to avoid.

So the bottom line is that the independent state legislature doctrine hangs out there, as a ticking time bomb, waiting to go off in a future case.

[This post has been updated.]