A few days ago, John Hinderaker had a long post criticizing Justice Ruth Bader Ginsburg's defense of the Supreme Court's use of foreign law. Paul Mirengoff adds to John's post the statement:

It won't happen, of course, but I think there's a case to be made for impeaching Justice Ginsburg.

Paul then repeats his claim in a post of his own:

Last night, John criticized Justice Ginsburg for her speech in South Africa defending the use of foreign law and court decisions to interpretation of the American Constitution. I suggested that a good case can be made that Ginsburg should be impeached. That case will become even stronger to the extent that her willingness to use foreign law continues to inform her opinions.

I find the current debate over the Supreme Court's reference to foreign law somewhat strange, since the Supreme Court has cited foreign law for almost all of its history. In a new manuscript by my colleague Steve Calabresi and Stephanie Zimdahl, they document nearly all the uses of foreign law in the Court's history. It can be downloaded from SSRN at the end of their long abstract here.

Calabresi and Zimdahl take a somewhat more nuanced approach than does either Justice Ginsburg or her critics:

This Article [describes] . . . what the Supreme Court's practice has actually been from 1789 to 2005 with respect to citing foreign sources of law. We will show that the Court's citation of foreign sources of law in recent years is not unprecedented as Justice Scalia implies, but that citation to foreign sources of law is increasing in the modern era in ways that may be very problematic. We show that there have been some dramatic, if not notorious, instances of the Court citing foreign sources of law historically, as happened for example in the Dred Scott case and in the anti-polygamy case, Reynolds v. United States. Moreover, we will show that the debate over citing foreign sources of law in American judicial decisions is not a new one at all. Indeed, the practice was debated as early as 1820 when Justice Livingston, in a sentiment echoed many years later by Justice Scalia, responded to Justice Joseph Story's citation of foreign sources of law in a Supreme Court case to provide a definition for the crime of piracy, by stating that it it is not perceived why a reference to the laws of China, or to any other foreign code, would not have answered the purpose quite as well as the one which has been resorted to. Thus, Scalia's modern lament finds an echo as long ago as 1820 in the U.S. reports. . . .

This article thus examines the many instances between 1789 and 2005 in which the Court has cited foreign sources of law and points out that several themes become apparent. First, on some occasions, the Court cites such sources as evidence of the reasonableness of its decisions: foreign practice is reviewed as to whether an American practice is reasonable or unusual. Second, we think it is striking that the three Justices who have historically been most likely to cite foreign sources of law in their opinions, Justices Joseph Story, Felix Frankfurter, and Stephen Breyer, were all, at some point in their careers, professors at Harvard Law School. This suggests a Harvard nexus to the debate over citation of foreign sources of law, which has gone previously unobserved. . . .

Our analysis of the Court's practice leads us to several conclusions.

First, we believe those who say the Court has never before cited or relied upon foreign sources of law are clearly and demonstrably wrong. In fact, the Court has relied on such sources to some extent throughout its history.

Second, the Court has, however, cited foreign sources of law with much more frequency in far more important constitutional cases in recent years, as Justice Scalia has suggested, and in addition the Court has tended to cite foreign sources of law in some of its most problematic opinions such as Dred Scott, Reynolds, and Roe v. Wade. This suggests Scalia is right to be wary of the Court's new trend in this direction.

Third, as Professor Calabresi has argued elsewhere, citation to foreign law is most justifiable when the U.S. Constitution asks the justices to weigh whether a certain practice is reasonable, as it does in the Fourth Amendment, or whether it is unusual, as it does in the Eighth Amendment. In contrast, citation to foreign law is least justifiable when the Court is asked to determine whether an unenumerated right is deeply rooted in American history and tradition, as was the case in Lawrence, or whether a federal statute violates American federalism rules, as it was asked to do in Printz v. United States. In these cases, we agree with Justice Scalia that the Court's task is to interpret the original meaning of our Constitution and not to determine the current day reasonableness or unusualness of a legislative practice. We thus think, with Justice Scalia, that in the over-whelming majority of non-Fourth and Eighth Amendment, it will not be appropriate for the Supreme Court to cite foreign sources of law. Citation of such law is, in fact, a sign that the Court is falling into policy-making, as it did in Dred Scott, Reynolds, and Roe v. Wade, and this in turn suggests the justices are behaving illegitimately.

While John and Paul make several good points in their critiques of Justice Ginsburg's speech on foreign law, the case for Justice Ginsburg's impeachment is neither outlined by Paul, nor do I see any serious basis for it.

I don't know whether a Justice should ever be impeached for holding a bad judicial philosophy, but such a philosophy would have to be far more unusual than Justice Ginsburg's to form a plausible basis for impeachment. By the way, I don't read Paul as actually advocating that Ginsburg be impeached, just opining that a "good case" could be made for such a move.