Vice President Joe Biden said on Wednesday that he sees a “less than even chance” that the U.S. Congress approves the 12-country Trans-Pacific Partnership trade pact before the next administration takes office in January.

Biden, speaking to the Council on Foreign Relations in New York, said that the brief “lame duck” session of Congress after the Nov. 8 presidential election was “our only real shot” for approving TPP.

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The sweeping trade deal has been a central plank in President Barack Obama’s foreign policy shift to counter the rising economic and military might of China, and has been broadly supported by U.S. business interests.

But the TPP is opposed by both the Republican and Democratic presidential candidates, who have blamed trade deals for U.S. job losses.

Senate Majority Leader Mitch McConnell, a Republican, has said the TPP would not get a Senate vote this year, and House of Representatives Speaker Paul Ryan has said he does not see enough votes for it to pass.

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“Sometimes when there’s no election to face and people are leaving and others who are staying, they may see the wisdom of TPP,” said Biden, who was a long-time Democratic senator, calling the post-election session “our only real shot” at passing the deal.

“But it’s going to be hard. I think it’s less than an even chance, but there is a genuine chance. It’s possible we can get it passed,” Biden said.