HANOI - Forty-one years after the end of one of the most divisive wars in American history, experts say ties between the U.S. and Vietnam have never been closer.

In fact, there are calls coming both from within the U.S. Defense Department and from the Hanoi government for President Barack Obama to further strengthen the relationship by completely lifting the decades-long arms embargo. Obama arrived early Monday for a visit to Vietnam.

The president has the power to bypass Congress and lift the lethal weapons ban on Vietnam on his own. But one U.S. lawmaker his administration likely would appreciate support from is Republican Senate Armed Services Committee Chairman John McCain.

McCain has witnessed the changes in relations firsthand between the two wartime enemies.

The Arizona senator and 2008 Republican presidential nominee was a young Navy aviator during the Vietnam War. His plane was shot down and he spent 5½ years as a prisoner of war in Hanoi, enduring torture and neglect.

But the decorated veteran bears no bitterness, as he told VOA in an interview.

“I think when we normalized relations that there was reconciliation between our countries and people," McCain said.

"Look, there are some individuals that mistreated me in prison that I hope I never see again. But that doesn't change my opinion that the Vietnamese people are wonderful and dear friends, and we need them and they need us – and I see a bright future in our relationships – with hopefully improvement on human rights issues," he added.

WATCH: VOA Exclusive interview with Sen. John McCain

McCain told VOA he has been back to Vietnam at least 20 times over the years, and he says the changes are profound.

He said he does not know what is on the president’s agenda, but he has a few ideas.

“I think he should raise our solidarity with Vietnam as regards to freedom of the oceans, that the Chinese behavior is provocative and in violation of international law, that our bonds of friendship and our relationship and things like scholarship programs and others and exchange programs are excellent – programs that need to be improved between our two military-to-military and such thing as humanitarian crises or disaster relief," the Arizona senator said.

"All of those need to be improved, American port visits. But the president should also point out that there is significant progress that needs to be made as far as freedom of speech, treatment of Buddhists, treatment of the minorities who live in the hills and mountains of Vietnam, and we expect those improvements to be made," he added.

Security issue

Brian Harding, Asia expert at the Center for American Progress, said security will be a major focus of the president’s talks.

“The U.S.-Vietnam relationship is trending in an extraordinarily positive trajectory. Top of the agenda for President Obama will be security issues, human rights and trade," Harding said. "I think all eyes, though, will be on whether the United States lifts its policy of an embargo of lethal weapon sales to Vietnam during this trip.”

The main sticking point over lifting the lethal weapons ban is Vietnam’s human rights record.

Human Rights Watch and other human rights groups say the Communist Party state has assaulted and imprisoned scores of rights activists and bloggers, and that it restricts freedom of speech, press and religion.

Catholic lawyer and blogger Le Quoc Quan (C), one
FILE - Catholic lawyer and blogger Le Quoc Quan, center, one of Vietnam's most prominent dissidents, speaks during his appeal trial at Hanoi People's Court of Appeals, Feb. 18, 2014.

John Sifton, Asia advocacy director for Human Rights Watch, said lifting the arms embargo would be “undeserved at this time,” calling the Hanoi government “one of the most repressive in the world.”

Harding agreed that the president must stand up for human rights wherever he goes. He said the Vietnam War still casts shadows in both countries, but the future looks bright.

“Vietnam is quite a young country demographically; its people, especially the young people have incredibly positive feelings towards the United States," Harding said.

On this trip, Obama also will visit Japan, another former wartime enemy, and is likely to highlight the power of reconciliation to transform ties in both countries.

President Obama’s Trip to Vietnam and Japan, May
President Obama’s Trip to Vietnam and Japan, May 23-27, 2016