President Obama is in Hanoi today as part of a three-day visit to Vietnam on his way to the G7 summit in Japan.

This trip comes at a critical moment for both Vietnam and the US – two countries with a long, complex relationship.

"This trip kind of marks the end, at last, for Americans of the Vietnam War and the establishment of a new kind of relationship with Vietnam," said David Brown a long-time US diplomat in the region and contributor to Foreign Affairs magazine.

That new relationship is influenced heavily by China's rising power in the region, including tensions over territorial disputes in the area, and a pending trade deal that is still working its way through US Congress.

The Vietnamese American community in Southern California is also paying close attention to the visit.

"My family – because of our history of being refugees – we're very concerned about the situation in Vietnam regarding human rights," said Tammy Tran, a resident of Garden Grove, whose parents fled Vietnam during the tumult of the Vietnam War era.

The President is scheduled to give a speech Tuesday in Ho Chi Minh City, laying out his vision for the next step in US-Vietnam relations. The visit comes amid street protests over the government's handling of a large-scale fishkill incident and criticism about political prisoners.