Obama will meet for the last time with G20 leaders in the Chinese city of Hangzhou, then attend a regional gathering in the reclusive Southeast Asian country of Laos. The stops comprise a six-day valedictory journey that will be the culmination of his effort to shift diplomatic and military muscle from Middle East quagmires to a dynamic region of vast economic potential.
"We see this trip as really bringing together a number of the President's top priorities really for the last seven and a half years," said Ben Rhodes, a deputy national security advisor and co-architect of Obama's Southeast Asia strategy.
But the tour is sure to highlight several growing challenges, including a newly assertive China more willing to throw its weight around in maritime security disputes and to nudge up against US air and naval forces in the region.
It will be nearly as difficult for Obama to ignore North Korea, with the Stalinist state already threatening to provoke the first crisis of the next president's administration with its accelerating missile and nuclear development.
Trade deal foundering
And then there's the uncertain fate of the 12-country Trans-Pacific Partnership (TPP), a years-in-the-making trade agreement that the Obama administration sees as crucial to anchoring the United States in Asia and ensuring that China does not get to set the rules of the road for regional trade.
The pact would create a vast free-trade zone, slash tariffs and harmonize regulation, linking countries in North America, South America, Oceania and East Asia that make up 40% of the global economy.
But the pact has been caught up in a backlash against global trade stoked by Donald Trump and Bernie Sanders in the presidential election. Even Democratic nominee Hillary Clinton, who as secretary of state enthusiastically backed the TPP, has repudiated it to preserve her political viability.
The administration still hopes Congress will ratify the TPP before Obama leaves office in January. But Republican Senate Majority Leader Mitch McConnell said last week that it can't pass in its current form and will need to be renegotiated by the incoming president.
Losing the TPP would not just be a blow to Obama's legacy but would also raise questions about America's long-term commitment to Asia once he has left office.
"For America's friends and partners, ratifying TPP is a litmus test of your credibility and seriousness of purpose," said Singapore Prime Minister Lee Hsien Loong during a visit to Washington this month.
"Asian countries want America to be engaged," he said. "But we need to know that this engagement will be sustained, we need to know that agreements will be upheld, and that Asia can depend on America."
Many Asian nations fear living in a region dominated by China -- and see America's presence as a counterbalance to Beijing's rising power. But if the United States doesn't ratify the TPP, its economic influence in the region is at risk of eroding.
"The bullet we won't dodge is when China goes into countries on the front line and says, as they have been saying by the way, 'We are here, we are not going away, you better think twice at what happens when President Obama leaves town,' " said Michael Green, formerly President George W. Bush's top East Asia policy official and now at the Center for Strategic and International Studies.
Obama's legacy in Asia will not exclusively be settled by the fate of the TPP, however. The White House believes it has reinvigorated US influence in a region whose security it has guaranteed for decades.
"As president, I have ... made a deliberate and strategic decision: As a Pacific nation, the United States will play a larger and long-term role in shaping this region and its future," Obama told Australian lawmakers in 2011 in a speech laying out his pivot. (The term was later refashioned as a "rebalance" after some US allies elsewhere wondered if Washington was deserting them.)
Signs of success
Indeed, his administration has racked up regional successes.
The US inked a major climate pact with China that has added momentum -- and pressure -- for other major countries to follow suit. America helped push once-pariah-nation Myanmar, also known as Burma, out of China's orbit and towards democracy after years of iron-grip military rule.
Obama built on the Bush administration's efforts to court India, the one regional power with the strategic potential to balance China. And his administration can claim credit for steady management of US alliances with key Asian allies South Korea and Japan, the latter of which recently made historic shifts to its pacifist post-war constitution for purposes of self-defense.
Michael Fullilove, executive director of the Lowy Institute, a top foreign policy think tank in Australia, agreed that Obama's policy has had its successes. "What has happened, though, is the pivot has run out of puff. It has come off of the boil," he said, pointing to a second-term foreign policy team less engaged in the region.
"The President has been distracted by other issues at home and abroad. The secretary of state is an unbeliever and the Congress and the media are agnostics," he said. "No one could look at US foreign policy and say it is really rebalanced at the moment towards Asia."
But it's not for lack of effort.
Obama, who spent four years in Indonesia as a boy, believes the future will be written in a thriving Asia rather than in a diminished Europe or the war-torn Middle East.
Obama has invested more time than any other president in working on Southeast Asia's political architecture, frequently attending regional summits. Washington has repaired an estrangement with Malaysia, lifted the decades-old ban on arms sales to Vietnam and patched things up with its old ally the Philippines. A new defense agreement with Manila will see US forces deployed to five bases near the contested South China Sea.
Obama has sent US military assets through waters and air space in the South China Sea claimed by Beijing to state the case for freedom of navigation -- even as his critics say he has done too little to respond to the Asian giant's increasingly overt territorial moves.
To reassure allies, US Marines have been rotating through the Australian port of Darwin. Meanwhile, Washington plans to operate littoral combat ships out of Singapore and base 60% of its naval strength in Pacific waters by 2020. During a trip to Japan in 2014, Obama reassured his hosts that US treaty commitments to its ally were "absolute" amidst rising territorial tensions between Tokyo and Beijing. At a summit in February in California with Southeast Asian leaders, Obama said that the aspirations of "all nations, large and small" should be upheld, in a warning to China about its maritime territorial claims.
But with Obama in the last few months of his presidency, key Asian powers are worried about the future with the 2016 presidential campaign upending US foreign policy orthodoxies.
Obama will be under pressure in Asia to reassure allies alarmed by Trump's questioning of US security commitments to partners in the region and American troop deployments.
Though dismayed about Clinton's turn against the TPP, Asian diplomats say she is a far more known quantity in the region and they are confident she would boost the pivot policy and take a tough line on Beijing.
China, for its part, has adopted a more confrontational stance partly rooted in the more aggressive personal political style that President Xi Jinping adopted after assuming China's top political and military posts in 2012 and 2013.
"There is some evidence to suggest that Xi and the people around him don't feel that the relationship with the US is as important as it might have been," said Aaron Friedberg, a former national security aide to Vice President Dick Cheney.
Many analysts believe the next president will face little choice but to inject more steel into US dealings with Beijing and expect that with Obama off the stage, China will seek to pose an early test for the new administration.