When a Supreme Court justice recuses himself from a case he or she has an interest in, there’s no shame associated with the decision — it’s the right call to avoid the appearance of politicking the issue. For so many reasons, it’s puzzling why Justice Antonin Scalia seems resolved to keep the focus of an upcoming case on himself rather than on the case’s appellant, Vice President Dick Cheney.

The applicable U.S. Code gives a simple standard for Scalia’s decision: “Any justice, judge, or magistrate of the United States shall disqualify himself in any proceeding in which his impartiality might reasonably be questioned.” It’s true that “might reasonably be questioned” is a pretty vague standard. But Scalia has completely misinterpreted the spirit of this law.

Scalia says a plane trip with Cheney to Louisiana for a day of duck hunting in early January shouldn’t call his partiality into question. He’s missing a critical point: A lot of people, including nearly every major newspaper editorial board in the United States, think we can’t know if Scalia’s vote would be tainted in this case, and are calling for one of the court’s more senior members to sit this one out.

Judges are used and taught to rule according to constitutional, federal, state and local laws, not popular opinion. But this is an exception: If there is widespread questioning of Scalia’s impartiality, that would seem to qualify as reasonable questioning.

And, all talk of semantics aside, one has to ask: What is Scalia’s agenda in doggedly staying on the case? Judges regularly recuse themselves from these types of cases, and the justice systems suffers no obvious ill consequences. What special power could Scalia’s input grant to the resolution of this appeal — other than a partisan reprieve for Cheney, Scalia’s longtime friend?

Speaking of party politics, for Scalia, the clincher in this decision should be the present political situation in the court. Forward-looking journalists and legal and political wonks have long been eyeing the retirements of the court’s most senior members, including perennial swing voter and oft-but-not-always conservative Sandra Day O’Connor.

Some are surprised that O’Connor hasn’t already left. Last September, the Chicago Sun-Times wondered whether she’s observed the difficulty President Bush has had winning Senate approval for his judicial nominees. Scalia’s intransigence can only make the Senate more fearful of politically extreme justices like those Bush is fond of nominating (a topic for another day) — especially when it’s time to nominate a lifetime justice to a starkly divided Supreme Court.

Scalia’s participation in Cheney’s appeal is not nearly worth the trouble.