Whatever else one can say about President Trump’s so-called travel ban, it has ignited a fabulous feud among the riders of the 9th United States Appeals Circuit. One has called the whole case a “folly” and likened it not just to a dog being wagged by its tail but also to a St. Bernard “being wagged by a flea on its tail.” It’s hard not to imagine that, from the high bench, the sages of the Supreme Court are enjoying the spectacle.

The business about the St. Bernard and the flea is from of one the clearest-thinking judges on the whole appeals bench, Alex Kozinski. He issued a dissent from the refusal of the 9th circuit to give a full, en banc review of a district court’s decision to block President Trump’s travel ban. He warns of a chilling effect of courts holding politicians to account for comments made on the stump.

Politico’s Josh Gerstein (our former coast-based national correspondent) has published a terrific summary of the feud, in which Judge Kozinski is but one of five circuit-riders who want the full bench to hear this case. A filing Friday, comprising ripostes from both sides, makes delicious reading. In it, one joey, Stephen Reinhardt, characterizes Judge Kozinski’s opinion as a “diatribe” and insists no issue is left for the appeals court.

Judge Kozinski fixes on two features of the current case. One is the question of due process. The reasoning of the 9th Circuit majority, Judge Kozinski points out, “rests solely on Due Process.” He goes on to point out, however, that the “vast majority of foreigners covered by the executive order” — being foreigners who have never set foot at America — “have no Due Process rights.”

It’s a devastating point. As Judge Kozinski sums it up, it means the court has supported an injunction against the President on “a rationale that applies to a small percentage of those covered by the President’s order.” It’s a point that really goes to the good faith of the 9th Circuit, which, we imagine, is why Judge Reinhardt and his colleagues are in such a defensive posture.

The “second peculiar feature” of the 9th Circuit’s opinion on which Judge Kozinski focuses is the Establishment Clause. That is the clause of the First Amendment that says Congress shall make no law respecting an establishment of religion. Judge Kozinski dissents from the Circuit’s willingness to bring into consideration President Trump’s statements made about Muslims in the thick of the election campaign.

An “evidentiary snark hunt” is the phrase Judge Kozinski uses for the 9th Circuit’s ruling. “This is folly. Candidates say many things on the campaign trail; they are often contradictory or inflammatory. No shortage of dark purpose can be found by sifting through the daily promises of a drowning candidate, when in truth the poor shlub’s only intention is to get elected.”

Warns Judge Kozinski: “No Supreme Court case — indeed no case anywhere that I am aware of — sweeps so widely in probing politicians for unconstitutional motives. And why stop with the campaign? Personal histories, public and private, can become a scavenger hunt for statements that a clever lawyer can characterize as proof of a -phobia or an -ism, with the prefix depending on the constitutional challenge of the day.”

“This path is strewn with danger,” Judge Kozinski writes. He warns it “will chill campaign speech, despite the fact that our most basic free speech principles have their ‘fullest and most urgent application precisely to the conduct of campaigns for political office.’” Does, he asks, a Meet the Press interview cancel out an appearance on Face the Nation? And what about “an overzealous senior thesis or a poorly selected yearbook quote?”

Judge Kozinski is sometimes called a libertarian. He certainly came by his love of liberty the hard way, having started out in life in the Stalinist youth of communist Romania. He was 12 when his family escaped with him to freedom in America. He so gloried in American liberty that but 14 years after he landed as a lad he was clerking for Chief Justice Burger. Even with all he’s achieved since then, this is certainly one of his finest hours.