Amid the pomp and ceremony of Barack Obama's trip to East Asia this week, the US president will be on a mission to quell doubts and anxiety.
While Obama will not be visiting China, its shadow will follow him wherever he goes on the four-nation tour, which begins on Wednesday.
In a region embroiled in disputes with China, the US president faces a series of balancing acts as he aims to demonstrate that America's much-vaunted "pivot" towards Asia is still a priority despite budgetary constraints. Among the trickiest of those balancing acts is projecting a calibrated effort to bolster Asian countries' faith in American commitments as not undermining Sino-US relations.
Obama will go out of his way to reassure Japan, South Korea, Malaysia and the Philippines of US commitment as he tries to make up for his no-show at the Asean summit six months ago because of a budget showdown in Washington, which was widely seen as undermining America's strategic rebalancing towards the Asia-Pacific.
One key message, analysts say, will be that Washington will not shy away from Asian countries' territorial disputes with an increasingly assertive China.
Such concerns have been compounded by Russia's annexation of Ukraine's Crimea region, which met little resistance from the US, Europe and international institutions.
The US response to Crimea's seizure shows how limited its options are when it comes to territorial disputes in Asia, says Ian Storey, a senior fellow with the Institute of Southeast Asian Studies in Singapore.
"If countries around the world, including in Asia, perceive the US response to be weak and ineffectual, then it might embolden them to pursue more confrontational policies with their neighbours," Storey says.
"The crisis over the Ukraine tests US credibility and leadership, and so Asian states will be monitoring Washington's response carefully."
Despite Washington's repeated assurances that the disputed islands in the East China Sea, known as the Senkakus in Japan and the Diaoyus in China, are covered by the mutual defence treaty between the two countries, many in Japan worry whether the US would come to its defence if conflict broke out with China.
Meanwhile in the Philippines, which has sternly challenged Beijing over territorial disputes in the South China Sea, a deal allowing a greater US military presence is expected to be formally signed by Obama and his counterpart, Benigno Aquino. But some in Manila are sceptical that the pact will offer meaningful protection against China.
"The deal will allow more rotational troop presence, more joint military exercises, but it will go nowhere close to what the Philippines really wants, which is access to US military hardware and a clear commitment that it will come to our assistance in the event of conflict with China," said Richard Heydarian, a political science lecturer at Ateneo De Manila University in Manila.
Manila's 1951 mutual defence treaty with Washington does not cover claims in the South China Sea, which were formalised in 1978.
"The last thing the US wants is to cross the red line, which is when China sees American allies using American weapons against China," Heydarian says. "People in the Obama administration know China is the most important bilateral relationship."
The US has recently stepped up its rhetoric against what it describes as China's intimidation in the region.
In February, assistant Secretary of state for East Asian and Pacific affairs Danny Russel questioned the legality of China's claims in the South China Sea in congressional testimony - a break from Washington's traditional neutrality on the issue.
Defence Secretary Chuck Hagel called on China to respect its neighbours during a trip to East Asia this month.
But questions remain as to whether concrete measures will be announced and, if they are, whether they will deter China.
"I could be wrong, but it's going to be a lot of rhetoric about 'Yes we support you and we are committed', but then what is the concrete action?" Storey says.
Professor Robert Sutter, of George Washington University, says while Japan and the Philippines are seeking a strong commitment from the US, South Korea and Malaysia will be concerned by rising tensions between Washington and Beijing.
"I am not sure if the president will say too much about [China's challenge] directly. I think he has to do this indirectly," says Sutter, who has worked for various government agencies on Asian affairs.