He was awarded a Silver Star for beaching his boat after a rocket attack and racing ashore to chase down and kill a Viet Cong fighter armed with a rocket launcher.
Nearly 40 years later, as incoming chairman of the Senate Foreign Relations Committee, Kerry favors using hot pursuit against pirates in the waters off Somalia, but urges a cautious approach before U.S officials consider sending American forces to chase them ashore. Kerry plans committee hearings next year looking at the problems posed by piracy.
The Massachusetts Democrat, who was on President-elect Barack Obama's short list to be secretary of state, said a hot pursuit policy on Somalia's coastline is "long overdue." But he warns against any "haphazard, sloppy" military missions.
"You gotta know what you're getting into and where you're going and under what circumstances," Kerry, a decorated Vietnam War veteran, said in a recent telephone interview with The Associated Press. "I mean, if you send five police officers raging into the center of Mogadishu, you are asking for trouble. You gotta be smart."
Responding to the growing problem of piracy in Somali waters, the U.N. Security Council voted unanimously earlier this month to authorize nations to conduct land and air attacks on pirate bases.
The resolution could set the stage for increased American military action in Somalia, a chaotic country where a U.S. peacekeeping mission in 1992-93 ended with a humiliating withdrawal of troops after a deadly clash in Mogadishu. The book and movie "Black Hawk Down" portrayed the ill-fated operation.
The senator said he was mindful of the dangers of hot pursuit cases, particularly given his Vietnam experience and his work as a longtime member of the Foreign Relations panel.
"If you've just got one patrol boat and it chases guys in and people go ashore without enough firepower, without knowing what they're up against, you can get into a lot of trouble," Kerry said.
Kerry knows hot pursuit cases can be ripe for controversy. As the Democratic nominee during the 2004 presidential race, Kerry was accused by some former swift boat veterans of lying about the Silver Star he won as a result of the onshore confrontation in South Vietnam's Mekong Delta.
When Kerry's boat crew came under rocket attack during coastal operations in February 1969, he ordered his men to beach the boat. An enemy fighter armed with a rocket launcher sprang up 10 feet (3 meters) away, aiming at the Americans. The fighter hesitated, then turned and fled. Kerry ran ashore, chased him and killed him.
During the 2004 race, a book entitled "Unfit for Command," by John O'Neill and Jerome Corsi, assailed Kerry's military record and claimed he earned his Silver Star not in a barrage of enemy fire, but rather by killing a fleeing Viet Cong teenager. The group Swift Boat Veterans for Truth also ran campaign ads questioning Kerry's military service.
Kerry's plans for looking into the impact of international piracy follow one of the Bush administration's last major foreign policy initiatives.
Some military officials have questioned the plans. Vice Adm. Bill Gortney, commander of the U.S. Navy's 5th Fleet, said it is hard to identify pirates and warned innocent civilians could be killed. The risks, Gortney said earlier this month, "cannot be overestimated."
Pirates have attacked more than 90 vessels and seized about 40 boats carrying goods to luxury yachts off Somalia's 1,880-mile (3025-kilometer) coastline. The ransom from their seizures has totaled about $30 million.
"It's bizarre," said Kerry. "You look at the amounts of money they're paying out in ransoms and it's incredible."