The trade agenda for President Obama passed a major hurdle with a key victory Tuesday when the U.S. Senate voted to advance legislation to allow the fast-track approval of big international trade bills.

The outcome of the key procedural vote was in doubt as a group of 14 Democrats who are pro-trade weighed whether to continue supporting the bill due to concern that a related package for workers assistance might not be approved in both chambers.

However, following repeated GOP congressional leaders assurances that the workers’ assistance measure would be adopted, 13 of the 14 backed the trade bill.

The vote ended 60 to 37 in favor, passing by what is the slimmest margin that is needed. A final vote in the Senate on fast track could come later Tuesday afternoon and would then go to the desk of President Obama to be signed.

The vote was very close as one of the Republicans who had supported the same measure during the past, Ted Cruz a Texas senator, said on Tuesday he would be voting against the measure.

Senator Mike Enzi a Republican from Wyoming, who was not present during the first measure, voted in favor of the bill, making up for the vote lost amongst the Republican senators.

The 14 Democrats who were pro-trade and supported the original version of the bill, known as the Trade Promotion Authority, when the bill was packaged with another bill that provides for retraining and other assistance measures for workers who lose employment due to large international trade agreements.

Passage of this fast-track authority along with the workers’ assistance measure, allows President Obama to complete a big trade deal in the Pacific known as the Trans-Pacific Partnership, which would link the economies of the U.S., Mexico and Canada with a number of Pacific and Asian countries.

This deal would give the United States an increase in its influence across the region, a top priority for the Obama administration.

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