We know that the five former Memphis police officers accused of murdering Tyre Nichols have been charged on the state level in Tennessee. But we also know that federal authorities are investigating as well, prompting the question of whether the ex-cops can be charged and potentially convicted federally, too.

The answer is yes.

It might surprise some people to learn that, under a longstanding legal doctrine called “dual sovereignty,” it’s not a double jeopardy violation when the cases are brought on both the state and federal level.

First of all, where do double jeopardy protections come from? They come from the Fifth Amendment, which contains multiple rights (including the right against self-incrimination, as the Jan. 6 committee depositions reminded us). When it comes to double jeopardy, the amendment protects against being put in that legal danger twice for the “same offence” (or “offense,” as we spell it these days).

But because the feds and states have their own crimes, it’s not the “same” crime, technically, since one is state and the other is federal. The Supreme Court had the chance to do away with the doctrine in 2019 but decided to keep it.

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Indeed, the ability to bring additional federal charges has been an important tool for civil rights prosecutions. The case against the Los Angeles Police Department officers who beat Rodney King in 1991 is a prime example, because some of the officers acquitted in state court were later convicted federally. (That 2019 Supreme Court case, Gamble v. United States, also raised the question of whether federal civil rights charges might be legal on top of state charges even without the dual sovereignty doctrine, but it wasn’t an issue because the court kept the doctrine.)

Importantly, though, it doesn’t matter if the first case results in a conviction; the second “sovereign” can still bring a successive prosecution. That’s what happened, for example, with former Minneapolis Police Officer Derek Chauvin, who was convicted on both the state and federal level in George Floyd’s 2020 murder.

So whatever happens in the state case against the ex-Memphis officers — we know at least two of them plan to plead not guilty — federal charges may legally loom.