Ernie Young's post at SCOTUSBlog raises a good point: while commentators tend to refer to "the Court" as a single entity, the Supreme Court consists of nine people with different views. In nonunanimous cases, "the Court" beomes a shorthand for the group of Justices in the majority.

  In federalism cases, moreover, there is no clear majority on the current Court. Four Justices — Stevens, Souter, Ginsburg, and Breyer — more or less share the same basic view that the Court has little to no role enforcing federalism constraints. The other five Justices would impose some limits on the scope of federal power, but don't really share common ground on exactly what those limits should be.

  Although classifying each Justice is quite difficult, a very rough first cut might be that Justice O'Connor tends to focus most on preserving a role for the states; Justice Kennedy on recognizing the dignity of the states and preventing federal overreaching; Rehnquist on restoring pre-1960s limitations on federal power; Scalia on finding and enforcing textual principles for limiting federal power; and Thomas on restoring an originalist vision of the Constitution. These approaches can overlap, and Justices might sign on to opinions that aren't exactly their cup of tea. But often they don't.

  The mathematics of federalism on today's Supreme Court, then, is that the four Justices who do not favor judicial enforcement of federalism constraints only need one additional vote to form a majority. Conversely, for the Court to rule in favor of a federalism limitation, common ground must exist that ties together the differing viewpoints of all five of the right-of-center Justices. The odds are that the former will happen more often than the latter, which is why victories for federalism principles have tended to be rare and on relatively narrow (that is, symbolic) issues.

  (Cross-posted at SCOTUSblog; leave comments here.)