I much appreciate Orin's response to my Morse v. Frederick post. Here is what strikes me as the heart of his claim, responding to point 2 of my post:

[Under Alito's approach, t]he speech is only unprotected if it advocates illegal drug use and can't reasonably be read as commenting about a political or social topic. Thus, student speech like "homosexuality is an abomination" would be protected because it makes a comment on a political topic....

Eugene next suggests that urging someone to violate the law is implicitly speech about a political topic. If you urge someone to break the rules, you must implicitly be arguing that the rule is bad. That makes some sense in theory, but it's not how I recollect high school. Back in high school, student opposition to school rules was partly about rebellion for the sake of rebellion. If school administrators announced a rule, a subset of students wanted to break it just for the thrill of opposing authority. That's what press reports suggest this case was all about; unfurling the banner was "a prank [designed] to cause a stir" rather than speech designed to communicate a particular set of views about a political or social topic. It's not the only way to interpret the banner in this case, but I think it's a plausible interpretation.

The trouble, it seems to me, is that under Justice Alito's test as Orin (quite plausibly) reads it, the rule is not that the speech is unprotected if "a plausible interpretation" of the speech is "break [the rule] just for the thrill of opposing authority." Rather, the speech is unprotected only if this is the only plausible interpretation — if the speech "can't reasonably be read as commenting about a political or social topic."

So under Orin's reading, "BONG HiTS 4 JESUS" should be protected so long as it can reasonably be read as commenting about whether marijuana use is good (a "social topic") or whether marijuana criminalization is good (a "political ... topic"). And it seems to me that it can be so reasonably read (even if it can reasonably be read as just a prank).

It's true that sometimes if you urge someone to break the rules, or praise conduct that breaks the rules, that can't reasonably be read as an implicit argument that the rules are bad. "Give your classmates wedgies" is probably not a protest against battery law, or an assertion that Nietzschean supermen shouldn't be bound by such law — perhaps one can say that it must either be a joke or a call to violate a rule without any commentary on the rule's soundness (though I'm not completely positive even about that). I take it this, though, that this is largely because there's no reasonable debate about whether wedgies are good, or should be allowed at school. Everyone agrees that battery should be against the rules; praise of such battery is thus unlikely to be an endorsement of the battery, or a claim that the anti-battery rules are bad.

But it seems to me that "[take] bong hits," "bong hits [are a good thing]," and "[we take] bong hits" — the three reasonable interpretations of the sign set forth by the majority, which Justice Alito joined and didn't try to limit on this score — aren't within this category. There is a lot of disagreement about whether marijuana use is good, and about whether marijuana law is bad. It seems to me that these three interpretations of the slogan (all treated as reasonable interpretations by the majority) can therefore be read as commenting on the soundness and wisdom of marijuana use, and of marijuana law. It thus seems to me that we can't say the poster "can't reasonably be read as commenting about a political or social topic." So if Justice Alito's test is read as Orin suggests, the test would indeed be internally consistent — but it would be inconsistent with Justice Alito's conclusion that the speech here is unprotected.