- "Federal marshals, don't move! River and Simon Tam, by the authority of the Union of Allied Planets, you are hereby bound by law."
- ―Agent McGinnis
One whole car of the train traveling on Regina (from Hancock to Paradiso) contained a regiment of federal marshals. One of the marshals attempted to stop Malcolm Reynolds and two of his crew from stealing a large shipment of Pescaline D, but was knocked out. The local sheriff, Bourne, requested the assistance of these marshals; his plea was rejected by an Alliance colonel countless miles away in deep space who had ultimate jurisdiction.
Months later, Agent McGinnis was an important federal marshal and had a small squad of subordinate marshals at his disposal at Saint Lucy's hospital on Ariel. They arrested Jayne Cobb and the siblings Simon & River Tam. One of them was killed by Jayne, while the rest, including McGinnis, were wiped out by the Hands of Blue using a highly-lethal sonic device.