As Threats to Oil Facilities Rise, U.S. Military Becomes Protector gives a short history of the Coast Guard:
The Coast Guard is serving as the oil police here [in the Persian Gulf]. It’s a somewhat novel role for the service, which traces its roots to 1790, when Treasury Secretary Alexander Hamilton cajoled a young and cash-strapped Congress to build a fleet of 10 cutters — called the Revenue Service — to collect tariffs. Coast Guard sailors pitched in during World War II and then patrolled Vietnam’s shallow waters two decades later.