Obama is travelling to Vietnam in turbulent times. Just a few days ago, its state-controlled media accused the US of supporting Viet Tan, branded a terrorist organization. Security forces blame the group - an underground network of activists largely located in the US - for the mysterious death of hundreds of tons of fish in the middle of the country, claiming it was done to topple the government ahead of last week's National Assembly vote.

The accusation though was largely a show for the domestic audience and won't overshadow Obama's state visit, said Gerhard Will, political scientist at the Berlin-based research organization SWP. "Strategic and economic interests are much more important on both sides," he believes.

A match made in China

It seems incredible that the US and Vietnam are on such good terms today, given that the Vietnam War ended just over 40 years ago. The path forward were largely forged in the late 1990s, with their relationship reaching its high-point in 2000, with a state visit by then-President Bill Clinton. Visits between high-ranking officials have since taken place regularly.

The two countries have worked out a comprehensive partnership agreement covering nine fields of cooperation. In addition to the further development of diplomatic and political relations, the partners seek closer cooperation in matters of war compensation and collaboration in scientific research. Obama is expected to open an American-style university, partnered with Harvard University, in Ho Chi Minh City.

The rapprochement has been quickened in the past few years by growing tensions in the South China Sea, where Vietnam, China and a number of neighboring countries dispute the sovereignty of two archipelagos. Vietnam and the US "support the peaceful settlement of the dispute" though international law, said Carl Thayer, former professor of political science at the University of South Wales. In order to stand up to its large and rapidly militarizing neighbor China, Vietnam is dependant on outside support.

Weapons and capital

For this reason, Obama's announcement on Monday that the US was lifting a 40-year-old weapons embargo of Vietnam sends an important signal to the new ally. The president stressed that the move has nothing to do with China and everything to do with the long process towards normalizing relations.

Obama also expressed confidence in the progress of their economic relations. The cornerstone of this cooperation is the Trans-Pacific Partnership (TPP), the free-trade agreement worked out last year between the US and 12 Asian countries, China not included. At the top of Vietnam's list of priorities, said Thayer, is the "continued access to the US market on the best terms possible."

Limits to the friendship

Despite all of the recent progress, the rapprochement has its limits. First, there is the unchangeable fact of Vietnam's geography. It cannot escape the vast influence of China, and must always take its interests in account when making a decision.

In that sense, the relationship between Vietnam and the US will continued to be marked by a strong ambivalence. "Vietnam would like to always keep a door for itself open," Will said. But "this of course applies also to the US too," he added, because, regardless of the tension, China still looms as a potential trading partner.

Will also warns that the relationship needs to stay grounded. "The dilemma is that on the one side there are such high expectations, and on the other there are hardly any concrete goals that they want to achieve together," he said.Vietnam expects military assistance in response to China's actions in the South Chinese Sea. But what would that actually look like? Does Vietnam want American ships and aircraft to patrol the region? This is still unclear. It is one thing to agree to security cooperation on paper, and something entirely different to put it into practice.

Success story

Despite these restrictions, the rapprochement in general is a positive development, representing "one of the success stories of President Obama's signature initiative, the rebalancing towards the Asia Pacific," according to Thayer.

And both experts agree that things are likely only to get better. "President Obama is laying the foundations for a further deepening of the relationship, pursuing a similar foreign policy course as he did with Iran and Cuba," Will said, referring to two other countries who have recently found themselves on much better terms with Washington. He expects the course to continue after the end of Obama's term. Relations are so good, that neither Vietnam's newly chosen government nor the US' soon-to-be chosen government can tear the two apart.