Today the Supreme Court decided Hencely v. Fluor Corp. The vote was 6-3, though not the split you might be expecting. Justice Thomas wrote the majority opinion, joined by Justices Sotomayor, Kagan, Gorsuch, Barrett, and Jackson. Justice Alito dissented, joined by the Chief Justice and Justice Kavanaugh. This unusual divide is due to the subject matter: preemption.
You might think that the conservative view favors broad federal preemption, but this is not so. Justice Thomas has long been skeptical of federal preemption, as it intrudes on principles of federalism. Wyeth v. Levine (2009) is a prominent case where Justice Thomas voted with the liberals to reject preemption in a pharmaceutical case. I think Justice Gorsuch is in a similar spot as Justice Thomas. I am not entirely sure where Justice Barrett lines up, but in Hencely, she joined Thomas and Gorsuch.
Justices Roberts, Alito, and Kavanaugh, by contrast, are more traditional, and favor broader preemption standards. Thus it was not surprising they dissented here.
