In a historic move, the U.S. has fully lifted its arms sales embargo to Vietnam -- a decision driven by the strategic goal of countering China in the Pacific region.
While making the announcement on Monday in Hanoi, President Barack Obama explicitly said the step "was not based on China or any other considerations. It was based on our desire to complete what has been a lengthy process of moving towards normalization with Vietnam," The Washington Post reported.
But he later acknowledged that, like the U.S., Vietnam is concerned over China's provocations in the South China Sea and, in what has become a refrain among top government officials, said the U.S. would "continue to fly, sail and operate wherever international law allows," it reported.
Obama's stop in Vietnam was widely seen as enhancing his so-called "Pacific pivot" in the rebalance of U.S. forces to the Asia-Pacific region to meet the rise of China and Beijing's aggressive moves to assert sovereignty over the contested waters of the South China Sea.
Lifting the arms embargo could be seen as the natural progression of the closer trade and political ties between Washington and Hanoi since diplomatic relations were re-established in 1995, but human rights groups have argued that Vietnam should release political prisoners and end civil rights abuses before weapons sales are considered.
Vietnam's neighbors are also wary of arms deals.
Last week, Cambodian government spokesman Phay Siphan said that Obama's visit would "help with reconciliation of their relationship" but "we also heard that the visit will discuss weapons and military issues. Cambodia is a country that prefers building peace, so we don't support that," the Voice of America reported.
The visit and the possibility of arms deals could also renew the debates over the controversial legacy of the Vietnam War in the U.S., where the POW-MIA flag still flies over the Capitol.
"There are still a lot of ghosts around," former Defense Secretary Chuck Hagel, a former Army sergeant and Purple Heart veteran of Vietnam, told The New York Times. "There is still a great deal of debate about Vietnam and what it meant for this country."
Obama was joined on the trip by Secretary of State and Navy Vietnam veteran John Kerry. He was the third U.S. president to visit Vietnam following Bill Clinton in 2000 and George W. Bush in 2006.
Sen. John McCain, who spent nearly five years as a prisoner of war in North Vietnamese prison camps, last week urged Obama to lift the arms embargo on Vietnam.
"This symbolic ban of weapon sales is a product of our past history and an inhibitor of our future relationship," said McCain, a Republican from Arizona and chairman of the Senate Armed Services Committee who retired from the Navy as a captain. "The time has come for a full lifting of this prohibition."
He added, "Vietnam should be allowed to purchase land and sea-based platforms that facilitate the Vietnamese armed forces' ability to operate more effectively on, above, and within its territorial waters."
And Obama should use the visit to "call for the release of political prisoners and other activists who have done nothing more than exercise their fundamental rights," McCain said.