(AP) John Kerry returned Sunday to the winding waterways of Vietnam's Mekong Delta region where he once patrolled on a naval gunboat in the search for communist insurgents.
But nearly 50 years later, Kerry was promoting sustainable aquaculture and trade in a rapidly expanding economy rather than hunting Viet Cong guerrillas at the height of the Vietnam War.
As Kerry's boat eased off a jetty onto the Cai Nuoc River, the secretary of state told his guide: "I've been on this river many times." Asked how he felt about returning to the scene of his wartime military service for the first time, Kerry replied: "Weird, and it's going to get weirder"
On this tour, Kerry was clad in drab olive cargo pants, a blue-and-white plaid long-sleeved shirt and sunglasses instead of the uniform he wore as a Navy officer in 1968 and 1969. In a new role, Kerry was revisiting the delta's rivers that made a vivid impression on him as a young lieutenant.
Kerry, standing next to the captain and surveying the brown water and muddy banks, recalled the smell of burning firewood as his boat passed through small fishing villages.
At one point, a family in a sampan traveling in the opposite direction smiled and waved. Kerry waved back, and noticing the family had a dog on board, remarked with a smile: "I had a dog, too. Its name was VC." VC was the abbreviation for the Viet Cong, forces fighting the South Vietnamese and their U.S. allies.
Stopping in the village of Kien Vang, Kerry visited a riverfront general store and bought candy for a group of children.
Kerry addressed a group of older students and scientists, delighting them first with a few words of Vietnamese before speaking strongly about the need to combat climate change.
"It is obviously amazing for me to be here today," he said. "Decades ago on these very waters, I was one of many who witnessed the difficult period in our shared history."
"Today on these waters I am bearing witness to how far our two nations have come together, and we are talking about the future and that's the way it ought to be."
That future, especially for the water-dependent economy of the millions who live in the Mekong Delta, is threatened by rising sea levels and planned upstream construction of dams in China and Thailand.
Kerry said he would make it a personal priority to ensure that none of the countries that share the Mekong and depend on it for their survival exploit the river at the expense of the others.
Forty-four years ago Kerry first set foot in Vietnam as a U.S. Navy officer who volunteered for service because, as he has said, "it was the right thing to do."
He was decorated with three Purple Hearts, a Silver Star and a Bronze Star for fighting in a conflict that he came to despise and call a "colossal mistake," one that profoundly influenced his political career and strategic view.
"When I came home after two tours of duty, I decided that the same sense of service demanded something more of me," he wrote in his 2003 book, "A Call to Service," as he was unsuccessfully campaigning for the presidency.
"The lesson I learned from Vietnam is that you quickly get into trouble if you let foreign policy or national security policy get too far adrift from our values as a country and as a people."
He arrived back on Saturday for his 14th trip to the country since the war's end but his first in 13 years, determined to bolster the remarkable rapprochement that he had encouraged and helped engineer as a senator in the 1990s.
In the city he first knew as Saigon, the capital of the former South Vietnam, Kerry met Saturday with members of the business community and entrepreneurs to talk up the Trans-Pacific Partnership, a broad trade agreement that the U.S. is now negotiating with Vietnam and nine other Asian countries.
To take full advantage of the deal's economic opportunities, Kerry said Vietnam, which has been widely criticized for its human rights record, must embrace changes that include a commitment to a more open society, the free exchange of ideas and education.
He made the comments after attending Mass at Notre Dame Cathedral, built in the 1880s and 1890s under French colonial rule, in a bid to show support for the tenuous freedom of worship in Vietnam. Vietnamese authorities have been criticized for harassing, prosecuting and jailing Catholic clergy.
In later talks with Vietnamese officials in Hanoi, Kerry was expected to make the case that respect for human rights, particularly freedom of speech and religion, is essential to improved relations with the United States. He also was expected to raise the issue of political prisoners whom the United States would like to see released.
The chief focus of the discussions, however, was expected to be maritime security and territorial disputes in the South China Sea.
Vietnam and other members of the Association of Southeast Asian Nations are deeply concerned about China's growing assertiveness. They are looking to the United States to serve as a counterbalance by stepping up its traditional role as a guarantor of security in the Asia-Pacific.
The Obama administration has pledged to do so as part of its self-described "pivot to Asia," with calls for a binding code of conduct on the high seas to ease tensions between China and its smaller neighbors over disputed territory.
China has reacted angrily to the U.S. approach. Earlier this month, over strenuous objections from Washington, Beijing announced a new air defense zone over parts of the East China Sea, where it has competing claims with Japan. Chinese officials have since said they might declare a similar zone in the South China Sea.
From Vietnam, Kerry will travel to the Philippines, which has its own maritime disputes with China.