Federal courts have sometimes blocked state prosecutions under that provision, out of concern that state authorities are using their prosecutorial power to frustrate the federal government from legitimately exercising its own powers, according to Bryna Godar, a staff attorney at the University of Wisconsin Law School’s State Democracy Research Initiative.
Godar wrote in the Lawfare legal publication that federal courts have repeatedly blocked state prosecutions when the federal official was reasonably carrying out lawful federal duties. But, outside those circumstances, courts have allowed the prosecutions to go forward.
“In many cases, the federal officer may ultimately walk away with immunity. But not always,” Godar wrote.