I enjoyed Eugene's post below, although I had a slightly different reaction. Eugene is quite right that "less is more" is a common phrase that is not meant to be facetious; as he suggests, it is often used to note that there isn't a linear relationship between the amount of something and its impact. Sometimes less of that thing actually increases its impact, so less in amount brings more in desired effect.

  At the same time, I read don't read Judge Bybee's dissent to call for a consideration of whether the phrase "less is more" makes sense, or what sense it makes. Rather, I think the difficulty was trying to transition from the clever and memorable intro, "Is less more?," into the legal question in the case. The second sentence doesn't do such a terrific job with it: "To lawyers, unlike philosophers, the question may appear facetious, but the answer has real-life implications." This gets the job done — it makes the transition — but doesn't make a great deal of sense for the reasons Eugene suggests. I think the better transition might have noted the difference between the contexts in which "less is more" and when it isn't. It's hard to come up with the perfect transition, but maybe something like this might be in the ballpark: "Is less more? Perhaps it is in fashion design, but the quip provides an unhelpful guide to interpreting statutes." Not great, but better, I think.