As much as 20 percent of the cocaine moving through South America ends up in the United States. Large amounts also travel across the ocean into Africa, providing funding for insurgents and drug traffickers, and then on up into Europe.
"We've had to cut back in hours and funding, and cut back on resources on the water," said Cmdr. Chris German, deputy chief of law enforcement for the 11th District, which stretches from Oregon to Peru. "The Coast Guard's aircraft and ships have cut back on fuel, so every hour we're not in the air or on the water, it does leave a gap."
Even so, sea smuggling has not grabbed the attention of lawmakers like the flow of illegal goods across the land border, where billions have been spent on beefing up security. Part of the reason is the challenge to patrolling the ocean.
With more than 42,000 active-duty members, the Coast Guard is assisted in the drug war by other U.S. agencies.
It works closely with other nations, but that help only goes so far. Bilateral treaties sometimes limit waters it can patrol, and some of the foreign navies are small and underequipped.
U.S. officials, for instance, cannot venture into Mexican waters without prior permission and will stop a chase and alert Mexican authorities if suspected boats cross into that territory. Treaties with nations such as Colombia allow U.S. authorities more latitude.
"The land border is a much simpler border to defend. You can put up fences. You can put people out there. But it's a finite area. You know where your land starts and where it ends," Papp said. "When you go out into the maritime, it's huge."
The Coast Guard oversees 95,000 miles of coastline and 4.5 million square miles of maritime territory where the United States has rights: "We don't have that many ships, and we don't have that many aircraft, so there are many different places and routes that the bad guys can take to try and get around us."