One problem in taking on pirates is what to do with them once they are arrested, Mullen said. There is a deal with Kenya to try pirates in court there, but so far, no pirates have been put on trial.
The United States is holding the lone survivor of the four pirates who took Phillips hostage and is trying to decide how to handle his legal case.
President Obama said Monday that he was determined to defeat piracy.
"I want to be very clear that we are resolved to halt the rise of piracy in that region and to achieve that goal. We're going to have to continue to work with our partners to prevent future attacks," Obama said Monday.
After the pirates faced down the U.S. Navy for five days, it was surprising to discover that most were between the ages of 17 and 19.
"Untrained teenagers with heavy weapons," Defense Secretary Robert Gates called them.
Harry Humphries, a former Navy Seal who is the founder of the Global Security Group Inc., said taking on piracy is too big a job for the United States to handle alone.
"We're in a bad situation if we're going to be given the mission of counterpiracy around the world," he told ABCNews.com. "We've got to get serious as an international community."
Humphries said Somali piracy is a very lucrative business run by clans in the Puntland region of Somalia. The clan leaders send out their teenagers to hijack ships, and the leaders keep most of the profits.
"If we start shooting these kids at sea, make it more difficult to get the vessels [it won't stop anything]," he said. "Until we go in there and take out the leadership, it's going to continue."
"The U.N. made it legal to go after pirates last year and to go into Somalia. Until that's done, this thing is going to continue," Humphries said.