If you're a judge, your first responsibility is of course to reach the conclusion that you think is legally right, and to explain it using those arguments that you think are most sound. But once you have that figured out, presumably you'd want to maximize your chances of being affirmed — since by hypothesis your approach is the correct one, and you'd like to see it kept rather than being overruled. And that must be doubly so when you not only think the result you reached is right, but are passionate about it.

You may sometimes render a decision knowing that it will be overruled, for instance because you think this is the decision mandated by current precedent, but you think the higher court will overrule that precedent or even somehow evade it. But once you figure out what you think is the right reasoning, it makes sense to present it as persuasively as possible, at least if you think it's likely that the decision will be appealed. In some cases, you might conclude that the higher court judges just won't care what you write, because they'll make up their minds based on their own considerations. Yet even in ideologically polarizing cases, there are usually at least some judges who may be swayed by persuasive argument, especially from a fellow federal judge.

By that standard, the judge's opinion in today's NSA eavesdropping case seems not just ill-reasoned, but rhetorically ill-conceived. A careful, thoughtful, detailed, studiously calm and impartial-seeming opinion might have swung some higher court judges (and indirectly some Justices, if it comes to that). A seemingly angry, almost partisan-sounding opinion ("[The orders] violate the Separation of Powers ordained by the very Constitution of which this President is a creature," emphasis added, thanks to a caller for pointing this out) is unlikely to sway the other judges — especially when the opinion is rich in generalities, platitudes ("There are no hereditary Kings in America and no powers not created by the Constitution"), and "obviously"'s, and poor in detailed discussion of some of the government's strongest arguments.

Jeff Rosen once faulted Justice Blackmun for a judicial approach that was so emotional that it undermined his ability to implement the very ideas that he passionately believed; his "tendency to let his heart get the better of his head," Rosen argued, would "deprive[] him of lasting influence." (Others have argued that Justice Scalia's pugnacity might have a similar effect.) It seems to me that by writing an opinion that was too much feeling and too little careful argument, the judge in this case made it less likely that the legal approach she feels so strongly about will ultimately become law.