This coming week the Supreme Court will hear argument in Bank Markazi v. Peterson (briefs etc here). Here’s what I’ve previously written about the case:

Bank Markazi v. Peterson … concerns nearly $2 billion in foreign currency reserves held in Europe by the Central Bank of Iran. The plaintiffs hold default judgments against Iran and tried to seize the assets. Under ordinary legal principles (the Foreign Sovereign Immunities Act, as well as various provisions of New York’s Uniform Commercial Code), the assets can’t be attached. The plaintiffs’ lawyers, however, persuaded Congress to enact the Iran Threat Reduction and Syria Human Rights Act of 2012….

The statute’s sole purpose was to dictate a result in this one case: by its terms, it applies only to “the financial assets that are identified in and the subject of proceedings in the United States District Court for the Southern District of New York in Peterson et al. v. Islamic Republic of Iran et al., Case No. 10 Civ. 4518 (BSJ) (GWG).” The statute provides that the assets “shall be subject to execution” upon only two undisputed findings: that Bank Markazi has a beneficial interest in the assets, and that no one else does. The statute preempts any contrary provision of New York law, and it specifically provides that is applicable to no other case.

United States v. Klein (1872) holds that Congress may not prescribe a rule of decision to the courts. That seems clear, and fundamental to the separation of powers. However, it’s actually amazing how narrow the principle is: Congress may change the substantive law for pending cases. (They’ll be decided under the new law.) The Court  distinguished Klein in Robertson v. Seattle Audubon Society, (1992), where Congress had enacted a statute to resolve—i.e., ding—two environmental suits by deeming certain forest management practices to satisfy applicable requirements.

It’s exceedingly hard to have any sympathy with the Petitioners here. After all, this is Iran, and the assets are sought to satisfy judgments for victims of Iran-sponsored terrorism. (Ok: the Bank isn’t technically the government of Iran, and this all happened before the President and Secretary Kerry put these people on their best behavior. But still.) For all that Congress’s action here—and the full-throated defense a DoJ, legislators, and various amici—has me nervous. I find it very difficult to articulate any meaningful difference between this statute and a legislative act that simply says: “A shall pay B a million bucks. And the federal courts shall rule accordingly.” (Various briefs try to distinguish this case; none look persuasive.)

The Founders were well aware of this menace of “trial by legislature.” Britain offered countless examples, as did the practice in the states. And we know the Founders didn’t like it: cases and controversies are for independent Article III courts, not for Congress. But how do these general precepts cash out—what are they worth, in real life? Not a whole lot. A few examples:

We know that Congress can’t re-open final judgments. Why not? Because if an independent judiciary means anything, it must mean that its judgments can’t be subject to executive or legislative revision. A true and important point—but not one of any great practical consequence. (E.g., Congress may pass a new law that gives plaintiffs a new case.)

Federal court jurisdiction comes from Congress (except in the handful of cases where it’s mandatory). Congress can withhold it. Presumably, though, it will still want to have stuff adjudicated. So: could Congress give that business to bodies other than Article III courts and vest “the judicial power” in those bodies? General answer: yes. Except it cannot divest the “core” of the judicial power in that fashion. Ironically that “core” is said to consist of state law claims over which federal courts barely have jurisdiction. It’s a bankruptcy thing. The entire adjudicatory machinery of the administrative state is left untouched.

Bank Markazi illustrates substantially the same difficulty. The Klein case mentioned earlier is notoriously opaque. The FedCourts profession’s perennial debate about the case is on display here in rival amicus briefs, both very good: Ernie Young on the Bank’s side (with obvious misgivings); Ed Hartnett and Erwin Chemerinsky on the Respondents’. At a minimum Klein seems to say something like this: Congress can obviously withhold jurisdiction. But it can’t keep the courts open and then instruct them to do something they deem unconstitutional. Even that much isn’t entirely free from doubt, though, and there’s a never-ending debate over whether any broader principle is at stake. E.g., could Congress (as here) enact a rule of construction that well-nigh dictates the result in a handful of known, pending cases? Or does it have to change the substantive law? Did it do so here—or did it merely instruct the courts to depart from otherwise operative law in this one case?

It’s one thing to spout separation-of-powers slogans. It’s fiendishly hard to formulate operational rules, and there’s the added question of whether the Court could actually sustain those rules over time against a Congress of a different mind. The case law illustrates the point. The Court likes to pontificate about its prerogative—in overwrought moments, its supreme and exclusive authority—to “say what the law is.” But in separation-of-powers cases of this sort, the Court (at least in modern times) doesn’t like to pick fights with Congress or to lay down hard rules. Usually, it avoids the problem by torturing some statute or changing the subject. Meanwhile, murky cases like Klein are left on the books—perhaps, to be mobilized when no other choice seems feasible.

Bank Markazi offers plenty of opportunities to steer clear of the cosmic issues (e.g., the mysteries and peculiarities of foreign sovereign immunity law). Considering how much could go wrong here, avoidance might not be a bad outcome.