US President Barack Obama's foreign policy pivot to Asia has taken a hit, and it came from a stalwart of his own party.
Democratic Senate leader Senator Harry Reid last week announced that he opposed legislation key to a trans-Pacific trade pact. That agreement is arguably the most important part of Obama's effort to step up US engagement in Asia.
Since Obama rolled out the policy, most attention has been on the military aspect, billed as a rebalance of US priorities after a decade of costly wars in Afghanistan and Iraq.
But officials have increasingly stressed that the shift is about more than military might, saying it would cement US stature as the pre-eminent Asia-Pacific power as China grows in strength, and capitalise on the region's rapid economic growth.
Hence the importance of the Trans-Pacific Partnership, a free-trade agreement being negotiated by 12 nations that account for 40 per cent of global gross domestic product.
Obama's Asia policy has been welcomed by countries leery of China's rise and territorial claims. During the president's first term, the US made headway in beefing up old alliances with nations like the Philippines, forging deeper ties with Indonesia and Vietnam, and befriending former pariah state Myanmar.
There were missteps. Rancorous politics at home forced Obama to withdraw from the East Asia Summit last autumn, raising some questions about his commitment to the region. New military deployments - a few hundred marines in Australia, new warships rotated through Singapore - have fuelled Chinese accusations of a US policy of containment while making little impact on regional security.
In Obama's state-of-the-union address last week, he urged both parties in Congress to back the partnership, saying it would open new markets and create American jobs.
But many of his fellow Democrats oppose trade deals negotiated by the administration that demand a simple yes-or-no vote, without the ability to make any changes. Reid said last week he opposed fast-track deals and that lawmakers should not push for them now, making it possible that legislation introduced three weeks ago will founder.
Many in the party side with unions in opposing lowered trade barriers, fearing job losses from increased competition.