By Richard Cowan and Krista Hughes
WASHINGTON (Reuters) - President Barack Obama's trade agenda, which focuses squarely on developing stronger ties with Asia, gets a shot at new life on Thursday when the U.S. Senate is set to hold an important test vote on legislation to help him complete a Pacific Rim deal.
Just two days earlier, Obama's own Democrats defied him and blocked consideration of the "fast-track" trade negotiating authority he needs to complete the Trans-Pacific Partnership (TPP) trade deal with 11 other Pacific Rim countries ranging from Chile to Malaysia.
Under fast-track, the U.S. Congress can approve or reject the TPP deal, but not amend its contents.
On this second try, enough Democrats are expected to support the legislation after they won the scheduling of a separate vote on a bill punishing countries that unfairly manipulate their currencies to keep their exports cheap.
"Though I am of course wary of counting my proverbial chickens before they are hatched ... I expect we will get a strong bipartisan vote in favor of finally beginning debate on these important bills," Senate Finance Committee Chairman Orrin Hatch, a Republican, said late on Wednesday.
The Senate is scheduled to vote on Thursday on an African trade bill that is expected to win strong support from Democrats and Republicans, as well as a customs bill containing the currency rules.
Assuming Senate Majority Leader Mitch McConnell musters the 60 votes needed in the 100-member Senate to limit debate on whether to bring the fast-track trade bill to the floor, senators are expected to spend at least part of next week debating amendments before voting on passage.
Left-wing Democrats want tougher controls on foreign labor and environmental standards, which they see as necessary to create a level playing field in any free-trade agreement the United States enters.
Some conservative Republicans, meanwhile, could end up voting against fast-track next week because they do not want to give Obama any new powers.
Even if the Senate approves the currency manipulation measure on Thursday, there is no guarantee the House of Representatives will embrace it. Furthermore, Obama could veto such a bill if it reached his desk, claiming it would threaten free-trade negotiations.
Trade is a hot-button issue with many Democrats in the United States, as labor unions and environmentalists - two of their important political supporters - are actively trying to kill fast-track.
Obama's aggressive defense of fast-track has put him at odds with the left wing of the Democratic Party, pitting him against Senator Elizabeth Warren, a leading liberal voice.
(Editing by Steve Orlofsky)