Slate has an interesting commentary which begins:

In 2003, Supreme Court Justice Anthony Kennedy penned a great gay rights opinion in which he ruled that no state may constitutionally criminalize gay sex. The case dealt with two men, John Lawrence and Tyron Garner, who, the court informed us, were arrested while having sex in Lawrence’s apartment. In overturning the conviction, Kennedy slammed the state for degrading the “dignity” of Lawrence and Garner’s intimacy and relationship, describing their sex act as “but one element in a personal bond that is more enduring.”

But there’s a problem with these statements. Lawrence and Garner weren’t really having sex when the police entered the apartment. They weren’t even in a relationship. Kennedy rested his holding on fabrications—but through the power of the court, those fabrications were woven into law.

How could a Supreme Court justice be suckered into believing a set of facts with no bearing in reality? Actually, it happens pretty often. As Adam Liptak’s recent investigation illustrates, many of the justices have rather poorly calibrated bullshit detectors. Justice Samuel Alito recently cited a statistic about employee background checks that is, by most accounts, made up; Kennedy has relied on his intuition to assert that “an increasing number of gang members” are entering prison. Even Justice Stephen Breyer, whose usual fact fixation has led him to affix epically long appendices to multiple opinions, has gotten a little lazy, once citing a statistic that originated on a blog that has since been discontinued.

One possible culprit for the court’s sloppy fact-finding is the sudden profusion of amicus curiae (“friend of the court”) briefs. These briefs, written by third-parties with interests in the case, were once fairly limited; today, a high-profile case can draw dozens or hundreds of them. (Scores of groups filed amicus briefs in United States v. Windsor, from ex-gays to ex-ex-gays.) Nowadays, writing amicus briefs is nearly a profession in itself, as nonprofits, for-profits, cities, states, congressional representatives, and law professors compete to sway the court in their direction. Given the authors’ vested interest in a particular outcome, a number of these briefs are high on ideology, not so high on strict factual rigor.