The recent release of Justice Harry A. Blackmun's private Supreme Court case files has starkly illuminated an embarrassing problem that previously was discussed only in whispers among court insiders and aficionados: the degree to which young law clerks, most of them just two years out of law school, make extensive, highly substantive and arguably inappropriate contributions to the decisions issued in their bosses' names. Even Roe vs. Wade, Blackmun's most famous decision, which legalized abortion nationwide in 1973, owed lots of its language and much of its breadth to his clerks and the clerks of other justices. A decade later,...