Greg Sidak has written a brief and elegant meditation on the difference between freedom of expression and freedom of speech. He reminds us that speech has at least this distinct advantage: it tends by its nature to be more precise than mere expression. Ambiguous “speech,” as expression tends to be, carries with it most of the costs and fewer of the benefits of what one might term its equivalent in speech. Burning the American flag is one thing, but its near-equivalent in speech—“I contend that this flag is a symbol of oppression, not freedom . . . !”—is something else. Few thoughtful Americans would say that speech of this sort should be banned, at least not in most imaginable circumstances, but some at least claim flags should be protected from intentional, fiery destruction.

Sidak is correct to point out this difference, but there are many differences within the category of speech itself that make it only too susceptible to regulation. Some speech needs to be prohibited or at least limited, but hardly anybody agrees on what. There are also categories of expression that ought to be robustly protected. A brilliant constitutionalist could perhaps capture these distinctions abstractly in words (or perhaps expressions), but I doubt it.

The question is, does banning the burning of the American flag constitute a futile gesture of resistance, or does it build a bulwark of sand that might resist a least a few of the incoming tides? Of course, allowing flags to be burned would assuage consciences liberal and (some) conservative alike that even such an acting-out was respected, despite its inflammatory and almost certainly incoherent message. Yet if expression must pass even some minimum measure of coherence, many a soapbox orator, that sturdy paragon of free-speech exerciser, one suspects, could be shut down by the police, even supposing the police could judge coherence. Probably many forms of expression that do not rise to the level of coherent speech must be allowed under any free-speech principle worth its salt. Coherent political speech should be at the top of the list and enraged rioters breaking windows much nearer the bottom of things protected under this principle. The top should be protected and the bottom not, and while judges must earn their keep making finer distinctions, the rest of us have every right to remain skeptical.