When Can States Prosecute Federal Agents?

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State and local law enforcement in Minnesota have said they are investigating federal agents’ killing of Alex Pretti and have gone to court to block federal officials from destroying or altering evidence. Videos show Pretti was disarmed and restrained on the ground when he was shot multiple times last weekend, part of a pattern across the country of escalating violence by federal officers. 

It’s not easy for states to prosecute federal law enforcement officers, particularly if federal officials impede an investigation. At the same time, states have more power than people may realize.

The law is clear that there is no absolute immunity for federal officers from state law, despite suggestions to the contrary by Vice President JD Vance and other Trump administration officials. Rather, state prosecutions are governed by a legal framework called supremacy clause immunity that stems from In re Neagle, an 1890 Supreme Court decision. 

The case itself is a wild story. David Neagle had been deputized as a federal marshal to protect U.S. Supreme Court Justice Stephen Field after David Terry, the former chief justice of the California Supreme Court, drew a knife on Field in a courtroom and repeatedly threatened to kill him. (Field had ruled against Terry and his wife in a case while sitting as a circuit justice.) When Terry later attacked Field on a train in California, Neagle shot and killed him. The local sheriff arrested Neagle for killing the unarmed assailant. 

The U.S. Supreme Court ruled that Neagle was immune from state prosecution, determining that he was fulfilling his duties as a federal marshal and did “no more than what was necessary and proper for him to do.” To rule otherwise, the Court explained, would allow states to interfere with the operation of federal law. 

It’s not hard to see how state criminal prosecutions could undermine legitimate federal law enforcement. In 1964, for example, local Mississippi officials sought to prosecute a federal marshal who used tear gas to control riots that erupted over James Meredith’s admission as the first Black student at the University of Mississippi. Citing In re Neagle, a federal district court blocked the state prosecution.

But while In re Neagle establishes strong protections for federal officers, it also leaves space for state prosecutions when officers act outside what’s “necessary and proper” to perform their duties. In 2001, for example, the Ninth Circuit allowed an Idaho county prosecutor to move forward with a manslaughter case against an FBI sniper who had killed an unarmed woman during the notorious raid of a cabin near Ruby Ridge, Idaho. Pointing to disputed facts about whether the agent acted reasonably, the court ruled that the prosecution should be allowed to proceed. The case was later dropped after the prosecutor left office; the Ninth Circuit vacated its ruling as moot.

And back in 1906, in a case with similarities to the Pretti killing, the Supreme Court allowed Pennsylvania to prosecute two soldiers charged with killing a civilian accused of stealing from a federal arsenal. Several witnesses said the man had already been captured when the soldiers opened fire. If true, the Court wrote, “it could not reasonably be claimed that the fatal shot was fired in the performance of a duty imposed by the federal law.” Similarly, during the Prohibition era, federal courts gave the go-ahead to state prosecutions claiming that federal officers had used unreasonable force in the course of their duties.

If Minnesota were to proceed with prosecuting federal officers, what would it look like in practice? If an officer raises supremacy clause immunity, the state would need to show that the officer’s actions were outside their official duties or that their conduct was unreasonable or unlawful (or at an early stage of the case, that there are disputed issues of fact as to these questions). 

Under existing law, defendants claiming supremacy clause immunity would also have the right to remove the prosecution to federal court. That means that while the case would continue to be prosecuted by state officials, federal judges would likely be the ones to oversee the case and consider the immunity claim. 

They would have their hands full. The last time the Supreme Court considered a case involving supremacy clause immunity was 1920, and lower courts have taken varied approaches to key questions, including what factors are relevant to assessing whether an officer’s conduct was necessary and proper. Among other things, this means that such a prosecution is likely to be slow going, entailing extensive briefing and appeals. 

Should a defendant in such a case be convicted, however, it would be for a state crime, and therefore not subject to the president’s pardon power.

To the extent that federal officials may see themselves as operating with impunity, the availability of state prosecutions is an important reminder: States have tools to hold federal officials accountable.

Alicia Bannon is editor in chief for State Court Report. She is also director of the Judiciary Program at the Brennan Center for Justice.

Suggested Citation: Alicia Bannon, When Can States Prosecute Federal Agents?, Sᴛᴀᴛᴇ Cᴏᴜʀᴛ Rᴇᴘᴏʀᴛ(Jan. 27, 2026), https://statecourtreport.org/our-work/analysis-opinion/when-can-states-prosecute-federal-agents