The Latest on Federal Question Jurisdiction: From Merrell Dow to Grable to... Gunn v. Minton?

The Supreme Court heard oral argument today in Gunn v. Minton—the latest in the Court’s long-running struggle to define when a federal law ingredient in a state law cause of action is sufficient for federal question jurisdiction (cases "arising under" federal law). 

Here’s the oral argument transcript, which includes this comment from Justice Scalia [p.16 of the transcript]:

"Well, I like -- I like bright-line rules. In fact -- you know, I thought Holmes had it right. It doesn't arise under unless the cause of action is a Federal cause of action."

Justice Thomas is on record as being receptive to the so-called Holmes approach (in his Grable concurrence, 545 U.S. at 320-21). He is not alone, apparently.

--A