Senate Democrats Tuesday successfully blocked a Republican move to start the formal debate on a law that would give President Barack Obama the power to unilaterally make international trade deals. The Trade Promotion Authority bill would also let Obama “fast-track” the huge and complex Trans-Pacific Partnership trade pact with 10 other Pacific Rim nations. The TPA the president wants would give Congress only an up-or-down vote on the whole package, without the ability to amend it. The Senate voted 45-52 against it.

Democrats generally oppose the TPP altogether, but a package with more Democratic-supported measures could gain enough votes in the future. In particular, Democrats shot down the deal in hopes of securing bipartisan support for two other trade provisions, the first of which would create an aid package for American workers who see their jobs move overseas because of eased trade tariffs. The second would obligate the government to enforce anti-currency manipulation laws abroad, which is expected to cause the most conflict. Without a majority in the Senate, Democrats are using their votes as leverage to get the majority they’ll need for those two provisions.

Only one Democrat, Sen. Tom Carper of Delaware, voted in favor of opening debate on fast track authority. He, like Senate Republicans, argued that the TPP would open foreign markets to American-made products, strengthening the U.S. economy and creating jobs. Democrats who oppose the TPP argue that its failure to address currency manipulation in countries such as Vietnam and China essentially endorses the practice, which could hinder American businesses' competition with companies in those countries that typically have much lower manufacturing costs. Sen. Orrin G. Hatch, R-Utah, said that while he is concerned about currency manipulation, to include the Democratic-backed safeguards “creates a whole new monster set of arguments and debates that we don’t need.

“I offered to have them bring up a bill later, do everything I can do give that a fair hearing, because I have concerns sometimes too,” Hatch said, according to the New York Times. “But on this bill we just can’t have it on there.”

Some Senate Republicans called the Democratic opposition to the bill proof of Obama’s unpopularity within his own party. That sentiment has some pundits speculating that the GOP leadership put the vote up to embarrass Obama. Others used it to criticize the Democratic Party as a whole.

Democrats in opposition to the bill brushed Obama’s “failure” off and said the bill simply had to include more robust protections for American workers. Democratic presidential hopeful Sen. Bernie Sanders of Vermont said the TPP is too similar to past trade deals like the North American Free Trade Agreement and the Permanent Normal Trade Relations with China that he says has seen jobs move overseas.

“These folks have been proven wrong time after time after time,” Sanders said in a speech on the Senate floor Tuesday. “The TPP would force American workers to compete against desperate workers in Vietnam who make 56 cents an hour. We have got to do better than that.”