As a young naval officer in Vietnam, John Kerry commanded a Swift boat up the dangerous rivers of the Mekong Delta. But when he returned there last month as secretary of state for the first time since 1969, he spoke not of past firefights but of climate change.
"Decades ago, on these very waters, I was one of many who witnessed the difficult period in our shared history," Mr. Kerry told students gathered on the banks of the Cai Nuoc River. He drew a connection from the Mekong Delta's troubled past to its imperiled future. "This is one of the two or three most potentially impacted areas in the world with respect to the effects of climate change," he said.