The fictional Rooster Cogburn, made famous in Charles Portis’ novel True Grit, is probably a bit too idiosyncratic—cranky, bellicose, boozy, trigger-happy—to be a successful modern-day U.S. marshal.

But as U.S. Marshal Anthony Gasaway explains, Cogburn’s story nevertheless reveals many truths about the professional duties and dangers faced by officers of the country’s oldest law enforcement agency. He discusses the history of the U.S. Marshal Service and the role it plays in law enforcement today in a program titled U.S. Marshals: A Popular History of the Nation’s Oldest Law Enforcement Agency.

Gasaway is the chief deputy U.S. Marshal, U.S. Marshals Service—Western District of Missouri.