US President Barack Obama landed in Vietnam late Sunday for a landmark visit capping two decades of rapprochement between the former wartime foes, as both countries look to push trade and check Beijing's growing assertiveness in the South China Sea. Air Force One touched down in Hanoi just after 9:30 pm (1430 GMT) for the beginning of a three-day trip in which Obama will meet Vietnam's communist leadership and stress improving relations with the dynamic and rapidly emerging nation.
For many Americans, Vietnam remains a painful byword for slaughter and folly since hostilities in the decade-long ruinous war between the two nations finally ended in 1975.
Yet few countries have seen such a dramatic turnaround in their relations since Obama's Democrat predecessor Bill Clinton normalised relations and later became the first post-war president to visit Vietnam in 2000.
The Obama administration now sees the country as a vital plank in America's much vaunted pivot to the Asia-Pacific region.
Vietnam's leadership hope to strengthen ties with the world's most powerful nation, particularly as it chafes with China over disputed waters.
"There always is an element of distrust in some sectors of Vietnam's elite, the political structure," said Murray Hiebert of the Center for Strategic and International Studies.
"But China's increased assertiveness in the South China Sea has really sharpened the Vietnamese mind and prompted Vietnam to probably move faster with the US than it might have otherwise."
On Monday morning Obama will meet the country's president, its prime minister and the country's de facto leader Nguyen Phu Trong, the general secretary of the Communist Party. Trong and Obama met last July, when he was given a prestigious Oval Office meeting.