The U.S. Supreme Court returns from the Thanksgiving holiday today to consider an enormously important labor law question: namely, what exactly a "supervisor" is under Title VII.

As they always do, SCOTUSblog did an outstanding job of previewing today's argument last week, but the short version is this: an African-American employee at Ball State University alleged that her supervisor harassed her, so she brought suit against her employer. However, the employee's supervisor did not have the authority to hire or fire her, so the question is whether this person is actually a "supervisor," as that term is used in discrimination cases.

The circuits have split on this question, but most courts acknowledge what everyone in the real world already knows: that not all supervisors wield ultimate employment power. When this case went up on appeal last year, the Seventh Circuit disagreed. Today, though, the only court that matters is the one holding the argument.

To say that the decision will affect existing and future Title VII litigation would be a gigantic understatement.