The vote was 67-28 and was seen in part as a proxy vote for the final tally. President Barack Obama considers the treaty his top foreign policy priority in the postelection Congress.
Almost a dozen Republicans joined all the Democrats in calling for an end to the debate. Vice President Joe Biden and Secretary of State Hillary Rodham Clinton were at the Capitol lobbying lawmakers.
Earlier in the day, Obama locked up the votes for ratification of the treaty as at least 10 Republicans said they would back the accord. A final vote is likely on Wednesday.
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