The Supreme Court handed down an opinion today in Wyeth v. Levine (here).

The Court revisited the always familiar issue of pre-emption that it ruled on earlier this year in Altria Group v. Good. In both cases, the Court struck down federal pre-emption claims and allowed state-level lawsuits against labeling regulations maintained by Congress.

Justice Stevens wrote the majority in both and was joined by Justices Kennedy, Souter, Ginsburg, and Breyer. However, is Justice Thomas’ concurrence in Wyeth does come as a bit of a surprise. The fact that he authored the majority in Altria Group makes his concurrence here somewhat particularly interesting. He concurs only in judgment and takes aim at the majority’s “purposes and objectives” test for deciding whether a federal law pre-empts state-law control.

The “Purposes and Objective” test asks whether or not a state-level regulation contradicts or impedes the “purposes and objectives” of the federal law in question. This gives states a heavier restriction than they would have if they were only barred from explicitly interfering with a federal statute (an idea advocated by only Justice Thomas).

This case should be a reminder to all the people who try to easily categorize justices into “liberal” and “conservative.” The traditionally “liberal” justices voted in favor of giving states the power to enforce torts that criticize and arguably impede federal law. “Conservative” justices wrote about the importance of vesting power in the federal government because of its expertise. Justice Thomas, often criticized and satired as being a lazy follower of the Court’s conservative wing, voted against them and authored what can only be described as a very unique opinion.