Alexandra Fay, Stephen Galoob, W. Robert (Will) Thomas, and Jeffrey Y. Zhang have posted “Testing McGirt” on SSRN.

Here is the abstract:

McGirt v. Oklahoma (2020) and Oklahoma v. Castro-Huerta (2022) reallocated criminal jurisdiction across federal, state, and tribal governments in eastern Oklahoma on a scale unmatched in modern American history. Three testable predictions framed the debate around these landmark decisions: (1) that the federal courts would be inundated and incapacitated (the Deluge Hypothesis); (2) that concurrent state jurisdiction over General Crimes Act cases under Castro-Huerta would either strengthen or undermine enforcement (the Dual Sovereignty Hypotheses); and (3) that Indian country defendants would face harsher or more lenient sentences in federal court than in state court (the Disparity Hypotheses).  

We test these predictions against a novel dataset of over 140,000 Oklahoma state criminal sentences and nearly 1,500 federal Indian country prosecutions hand-collected from PACER. Four findings emerge. State sentences imposed on American Indian defendants in the McGirt reservation counties fell by roughly 78%, while sentences elsewhere held steady or rose. The federal deluge was real but short-lived, consistent with the Oklahoma Court of Criminal Appeals’ 2021 decision against retroactive application in Matloff v. Wallace. Federal General Crimes Act filings collapsed after Castro-Huerta, supporting the warning that concurrent state jurisdiction would result in federal underenforcement. However, the increase in state prosecutions in the affected counties apparently subsumed the decline in federal prosecutions. And across every offense category we examine, federal sentences are equal to or lighter than their state counterparts.  

These empirical findings should inform the future of federal Indian law and policy. The restoration of reservation status triggers serious consequences for federal, state, and tribal courts, and these consequences can be managed without sacrificing the rule of law. McGirt challenged the federal courts but did not break the system. Courts can wield criminal procedural rules to limit the fallout of major jurisdictional change. Our findings also show that concurrent jurisdiction results in significant effects on criminal practice. For better or for worse, Castro-Huerta produced a substantial return of General Crimes Act cases to the state system. And despite their strained capacity, federal courts tasked with adjudicating Indian country crimes sentenced consistently throughout the surge, at levels at or below those of Oklahoma-one of the most punitive states in the Union.

Highly, highly recommended.