Luigi Mangione, who’s fighting separate state and federal cases for the death of health care executive Brian Thompson, reportedly said in court on Friday that it’s “the same trial twice. One plus one is two. Double jeopardy by any commonsense definition.”

Yet even if Mangione has a commonsense point, double jeopardy is an example of a legal issue that’s more complex than common sense might suggest. 

In 2019, the Supreme Court affirmed a long-standing legal theory called the dual sovereignty doctrine, also known as the separate sovereigns doctrine. Under that doctrine, multiple charges aren’t the “same” ones for double jeopardy purposes if they’re prosecuted by different “sovereigns.” 

Applying that doctrine to Mangione’s case, because New York state and the federal government are separate sovereigns, the fact that they’re both pursuing him for charges stemming from the 2024 fatal shooting in midtown Manhattan doesn’t mean they’re violating double jeopardy. 

“Under this ‘dual-sovereignty’ doctrine, a State may prosecute a defendant under state law even if the Federal Government has prosecuted him for the same conduct under a federal statute,” Justice Samuel Alito wrote for the court in 2019’s Gamble v. United States. He wrote that “a crime against two sovereigns constitutes two offenses because each sovereign has an interest to vindicate.” 

Gamble was a 7-2 decision, with Justices Neil Gorsuch and the late Ruth Bader Ginsburg dissenting. Since then, Justice Amy Coney Barrett replaced Ginsburg, and Justice Ketanji Brown Jackson replaced Justice Stephen Breyer, who was in the majority. Assuming all the other justices’ views from 2019 hold, even if Barrett and Jackson were to join Gorsuch in a future appeal pressing the issue, that would still be a 6-3 split upholding dual sovereignty.   

Gorsuch argued in his dissent that “[a] free society does not allow its government to try the same individual for the same crime until it’s happy with the result.” The Trump appointee lamented that his colleagues in the majority endorsed “a colossal exception to this ancient rule against double jeopardy.” In his majority opinion, Alito wrote that the U.S. “is a federal republic; it is not, contrary to JUSTICE GORSUCH’s suggestion, … a unitary state like the United Kingdom.”

So, despite Mangione’s commonsense claim, the law is more complicated, at least as a lopsided Supreme Court majority sees it. 

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To be sure, when the judge presiding over Mangione’s state case denied his double jeopardy motion in September (citing the Gamble precedent), the judge noted that New York state law grants greater double jeopardy protections. But the judge observed that those protections are only triggered when a prior prosecution ends in a conviction (by trial or plea) or once a jury is sworn. The judge deemed Mangione’s motion premature because neither event had occurred by that point. 

Though Mangione could still lose such a motion even if it becomes ripe to make, it could nonetheless stay premature if the current trial schedule holds. As it stands, Mangione is set to go to trial first in the state case, in June, and then in the federal case in September. The federal judge recently dismissed a charge that carried the possibility of the death penalty, and if the federal government appeals that ruling, then that could push back both trials. As a general matter, trial dates can shift for any number of reasons.

But however the scheduling and any potential appeals play out if he’s convicted in one or both cases, the law doesn’t necessarily treat the state and federal cases as, in Mangione’s words, “the same trial twice.” If he eventually takes the matter to the justices, the high court won’t likely be asking the simple question of whether or not that makes sense. 

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