Amid intense lobbying on both sides, House GOP leaders and the White House pressed ahead Wednesday in a final drive to find supporters for a major trade bill, as President Obama urged reluctant Democrats to support a plan that lays the groundwork for future votes on U.S. trade agreement with a group of Asian-Pacific nations.

"This is an agreement that the President believes is clearly in the best interest of middle-class families in the United States," said White House Press Secretary Josh Earnest, who told reporters that Mr. Obama was lobbying undecided lawmakers.

"The President and his team will continue to be engaged in the days leading up to the vote in convincing Democrats and Republicans to build the kind of bipartisan majority that we also saw in the Senate," Earnest added.

Up on Capitol Hill, Republicans were pressing GOP lawmakers to stick with the President, even though many would rather not give the Obama Administration any type of legislative victory.

"We all know that free trade is good for jobs," said House Speaker John Boehner, who acknowledged that this vote will go down to the wire.

"Trade votes are never an easy lift around here," Boehner told reporters at a news conference, as he said the GOP was seeing some "momentum" on the trade deal.

Most Democrats, pressed hard by Big Labor, are ready to vote against any trade plan, convinced it will cost American jobs in the long term.

"Fast track means that Congress only gets to vote up or down on a trade agreement without the opportunity to make any changes," complained Rep. Chris Van Hollen (D-MD), echoing charges made by some Republicans.

Votes on a series of trade-related measures could happen on Friday in the House.

Approval of the so-called "fast track" legislation would simply start a final push for negotiations on the Pacific trade deal, which would then be voted on at a later date in the Congress.

The details of that agreement at this point have been kept secret, which is something that has spurred opposition in both parties.