The U.S. House of Representatives will debate a package of bills central to President Barack Obama’s push for a Pacific Rim trade pact, with considerable doubt still lingering about the outcome expected by week’s end. The core of the debate is a bill, already approved by the Senate, that would give Obama “fast-track” trade negotiating authority. He says he needs this to promptly conclude a 12-nation Trans-Pacific Partnership (TPP) trade deal. The House was expected to vote on the fast-track measure on Friday. But over the next two days, a complex procedural dance will take place in the Republican-controlled House meant to solidify support from Democrats and Republicans. If fast-track is approved, it would go to Obama’s desk to be signed into law, empowering him to negotiate the TPP and reassuring Japan, the second-largest economy involved in the trade pact. Japanese officials have said that fast-track approval is needed for the creation of the pact, which would encompass 40 percent of the world economy. In an unusual coalition, the Democratic president and House Republican leaders are allied in supporting fast-track, with most Democrats opposed, as well as some Republicans. “Republicans have addressed both the substantive and procedural concerns” raised by House Democratic Leader Nancy Pelosi and other House Democrats, said Kevin Smith, a spokesman for Republican House Speaker John Boehner. The maneuvering will begin with an obscure bill aimed at encouraging trade with African nations. The measure now includes a provision important to Democrats to finance a program helping workers who lose their jobs as a result of trade deals. The program is known as trade adjustment assistance (TAA). On Friday, the House would then debate and take votes on the TAA bill itself and “TPA,” or Trade Promotion Authority, which is also known as fast-track. The failure of any one of these bills on Thursday or Friday could bring the entire initiative, a top priority of Obama’s, to a screeching halt, forcing Congress to figure out new ways to get the trade package to Obama’s desk. Early on Thursday, a Democratic aide familiar with the deliberations, said problems remained, including whether public employees impacted by trade could apply for worker assistance. “Labor unions are whipping members into a frenzy over the issue and this is very likely to be a major problem in getting significant House Democratic support for TAA,” the aide said.