Obama is slated to attend a summit of East Asian leaders in Cambodia this month, underscoring his commitment to the region. He could also make a side-trip to Myanmar, becoming the first US president to visit that military-dominated country to reward its democratic reforms.

Many Asian governments are likely to welcome Obama's victory over Republican challenger Mitt Romney. Concerned about China's rising power and assertive behavior, they have supported the Obama administration's "pivot" to the region as the US disentangles from the wars in Iraq and Afghanistan.

Still, they also want the US to get along with China, the hub of the Asian economy. Romney's more confrontational stance, based on his threat to designate China as a currency manipulator, could have set back US-China relations and even sparked a trade war.

Romney's defeat will be greeted with quiet relief in Beijing, which wants stability in its most critical bilateral relationship as it undergoes its own leadership transition that kicks off at a Communist Party Congress on Thursday.

Whether Asia policy gets the kind of attention from the US as during the first term will depend partly on who succeeds Secretary of State Hillary Rodham Clinton. She has made at least a dozen trips to the region and championed the view that US interests lie in more ties with that booming continent. Her hard-charging top diplomat for East Asia, Kurt Campbell, is also expected to move on.

The agenda of the next secretary of state, who is yet to be named, could be at the mercy of events.

Walter Lohman, director of Asian studies at the Heritage Foundation think tank, said China is the main long-term strategic threat for the US, but the most immediate foreign policy concern is Iran's nuclear program. A conflict there would suck up resources and could upset what the administration wants to achieve elsewhere, he said.

Fighting in neighboring Syria also shows no sign of abating. Security in Iraq remains fragile, and in Afghanistan, a withdrawal of US combat forces by 2014 leaves it vulnerable to the kind of civil war that blighted the country in the 1990s and led to a Taliban takeover.

Political problems at home could also cramp Obama's outreach to Asia.

His most immediate domestic challenge is an impending showdown over tackling the national debt that economists say could send the world's biggest economy back into recession.

Even before Obama gets to his second inaugural on Jan. 20, he must reach a budget deal with Republicans to prevent a combination of automatic tax increases and steep across-the-board spending cuts – dubbed a "fiscal cliff'' – set to take effect in January.

That would entail nearly $500 billion in defense spending cuts over a decade that could undermine plans to devote more military assets to the Asia-Pacific, where the increased capabilities of Chinese forces pose a growing challenge to US pre-eminence in the region.

China is already acting with growing assertiveness in the seas of East Asia.

Its territorial dispute over islands administered by US treaty ally Japan could trigger a military confrontation between Asia's two biggest economies. This year, China has already faced down the Philippines over sovereignty of a reef in the South China Sea, where the competition among China and its neighbors for fish and potential underwater oil and gas reserves could also sow seeds of conflict.

Two years ago, Clinton announced the US national interest in the peaceful resolution of South China Sea. That step irked Beijing, and managing those diplomatic tensions will be of growing importance in the second term. Washington supports efforts by Southeast Asian nations to negotiate collectively with China on the disputes, but China remains reluctant to play ball.

A strident nationalistic tone in China's state rhetoric in its dispute with Japan has fueled concerns that the Communist Party could increasingly resort to such patriotic appeals if China's juggernaut economy slows and public dissatisfaction with the party grows further.

Obama has attempted a balancing act in relations with Beijing, seeking deeper ties and encouraging it to play by international norms to ward off the possibility of confrontation, but also stepping up trade complaints in an effort to protect the interests of US companies.