Social media companies found much to like in last month’s blockbuster Moody v. NetChoice decision. Facing legislation that would have forced Facebook, X, and others to carry content against the companies’ will, a majority of the justices endorsed the idea that platforms retain a First Amendment right to editorial control that shields them from state efforts to dictate content decisions.

Why, then, did they lose the case?

The answer hinges on the type of claim at issue. NetChoice brought facial challenges to the Texas and Florida laws, arguing that these laws are per se unconstitutional. The Supreme Court held that the parties did not meet, and the lower courts did not properly consider, the stringent test required for such claims. It sounds like legal minutiae, but underlying the Court’s decision are fundamental questions about judicial authority and the separation of powers that the Court was right to surface.

A facial challenge is a claim that the law in question is invalid “on its face,” meaning it should be stricken in its entirety. This is a broader claim than the typical “as-applied” challenge, which asserts only that a particular application of the law is unconstitutional. By its nature, a facial challenge goes beyond the facts of the litigant’s case, often inviting the Court to speculate about the scope of the law’s coverage and how it may be enforced. Courts are uncomfortable with this task, and thus place a high burden on such plaintiffs. To win a facial challenge, a plaintiff must “establish that no set of circumstances exists under which the Act would be valid” or that the law “lacks a plainly legitimate sweep.” But recognizing the importance of free expression, the Court applies a slightly less stringent standard in First Amendment cases, requiring the plaintiff to show that “a substantial number of the law’s applications are unconstitutional, judged in relation to the statute’s plainly legitimate sweep.”

The NetChoice cases highlight the concern animating this heightened scrutiny. The majority seemed comfortable concluding that Texas’s and Florida’s laws were unconstitutional when applied to paradigmatic cases such as Facebook’s news feed and YouTube’s homepage. But at oral argument, the justices and litigants alike struggled to define the full scope of these laws beyond that core. Do the laws regulate other functions provided by social media platforms, such as direct messaging? What’s the full universe of companies covered? Do they reach Yelp reviews, Venmo transaction postings, or Gmail’s message filtering functions? Because the parties, and the lower courts, confined their analysis largely to those paradigmatic cases, the Court could not determine these laws’ full scope and therefore could not enjoin them entirely.

Justice Clarence Thomas wrote separately to highlight a more fundamental concern: that facial challenges are themselves facially unconstitutional. Thomas anchored this analysis in Article III of the Constitution, which permits federal courts to exercise judicial power over only “cases and controversies.” This limited power prevents federal courts from issuing advisory opinions unconnected to an actual case, and Thomas argues it equally precludes federal courts from pronouncing a statute unconstitutional to nonparties. “In practice,” he writes, “this provides federal courts a ‘general veto power’” over Congress and state legislatures in violation of the separation of powers and basic principles of federalism.

Thomas raises important concerns. Facial challenges threaten to short-circuit the democratic process by invalidating duly enacted legislation based on the Court’s speculation regarding how a law might be enforced. Generally, it’s wise to cabin the judicial power by anchoring its exercise to the facts of a particular case. But there are countervailing interests as well: invalidating unconstitutional laws only as applied to particular litigants creates legal uncertainty as to the scope of a ruling. Moreover, limiting plaintiffs to as-applied challenges can sometimes make a law practically unreviewable. As-applied challenges are typically reactionary, but sometimes the consequences of violating a law are so significant that few are willing to volunteer as test cases. The Court discussed this in Reno v. ACLU, a facial challenge to a law criminalizing the knowing transmission of indecent messages to minors online. Most would avoid posting anything even potentially approaching indecency rather than risk jail time to test whether and when enforcement might be unconstitutional.

Given the general confusion about the scope of the Texas and Florida laws, the Court was right to remand the case to sharpen the pencil on these claims. In light of the Court’s favorable discussion of Facebook and YouTube’s speech rights, NetChoice might shift to an as-applied challenge going forward. Or it might push the states regarding when and how these laws may be enforced. Either way, a more robust record will lead to a fuller treatment of the topic and a more nuanced understanding of the speech issues at stake in these important cases.

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