COD is for government

A 5-4 Court held in Shoop v. Twyford that a district court erred in ordering transportation of a prisoner to the hospital under the All Writs Act where the evidence to be obtained at the hospital would not be admissible under AEDPA. A jurisdictional problem popped up at SCOTUS--the transportation order was not final. The majority stated in a "terse" footnote that it was appealable under the collateral order doctrine because it burdens state sovereignty and creates public-safety risks; Justice Breyer dissented for Sotomayor and Kagan to argue this does not meet COD requirements; and Justice Gorsuch argued cert was improvidently granted because the Court did not take the case to extend the doctrine. At the very least, it required more than a footnote.

And this is an expansion, as the court of appeals held that state sovereignty that is implicated by any federal-court order compelling a state to do something. Breyer, likening the order to a discovery order, argues that having the state as appealing party should not convert an otherwise interlocutory order (such as a discovery order) into one subject to COD review.

Of course, the modern collateral-order doctrine is skewed towards appeals by the government as opposed to by private individuals. While not framed as "appeal is proper because this is the government," the unprotectable public interests justifying the COD arise most commonly where the government loses on a uniquely governmental issue--e.g,, individual-officer immunity, sovereign immunity, foreign sovereign immunity, discovery orders affecting foreign sovereign immunity. I do not expect, as Breyer  worries, a regime in which government can appeal a common order that a similarly situated private party cannot appeal; but it is not surprising to see COD review of a unique discovery order that applies only to government parties but never to private parties. For example, an order compelling transportation of a prisoner for discovery purposes applies only to government parties and is appealable; a common order compelling discovery, equally applicable to all parties, is not.