What Counts As "Business Law" Experience?

David Frum slammed Judge Sonia Sotomayor for lacking any meaningful business law experience. Bernard Harcourt cried foul. Paul Horwitz considers the evidence and renders a verdict (three actually).

An interesting sidenote: As one of Horwitz's commenters observes, Justice Thomas is the only member of the current court to have worked in-house for a corporation.

UPDATE: Frum defends himself from Harcourt here.