WASHINGTON - Countries negotiating a monster trade deal that would cover more than one-third of the world's economy may now have a new obstacle to contend with: resistance in the U.S. Congress.

President Barack Obama's Democratic allies in the Senate are making it increasingly clear that they won't grant him so-called "fast-track" authority to negotiate the Trans-Pacific Partnership deal, involving a dozen countries including Canada.

That means the other countries negotiating with the U.S. might now be left wondering whether the deal they're working out could subsequently be gutted by Congress, scuttling the whole process.

"I'm against fast track," Senate Speaker Harry Reid, who controls the floor schedule in the chamber, said this week.

"Everyone knows how I feel about this... And I think everyone would be well advised just to not push this right now."

That more vocal resistance comes after Obama included in his state of the union speech a request for a fast-track bill — or what's formally known as Trade Promotion Authority, which would force Congress to vote on a deal without amendments. The American constitution actually gives Congress, not the president, power to approve trade deals unless a fast-track bill says otherwise.

The White House has stated its desire to wrap up a deal in 2014. Canada and Mexico joined the talks in 2012, and the estimated size of the new trade zone would represent almost 800 million people in countries with a combined GDP of $27.5 trillion.

The Canadian government declined to weigh in Thursday on developments in Congress, saying fast-track legislation is an issue for American lawmakers to decide. In a statement, it added that it remained committed to opening new markets throughout the fast-growing Asia-Pacific region.

Trade issues have a strange habit of inverting the Washington political order: Democratic presidents have tended to get more support from normally hostile Republicans, while their Democratic allies turn on them.

That appears to be playing out again on the Trans-Pacific Partnership.

"The president's state of the union said he had a phone and a pen. I think the first phone call actually has to be to Harry Reid to talk about trade," Rep. Kevin McCarthy (R-Calif.) said Thursday.

"He might want to have to get his own party in line."

Some trade-watchers, however, were unconcerned with the latest developments.

There are pros and cons to fast track, says Robert Wolfe, a professor at Queen's University and former Canadian foreign-service officer who once specialized in trade.

He played down the Washington reaction to Reid's remarks as "inside-the-beltway stuff," noting Obama only made brief reference to it in the state of the union.

Wolfe said talks have been slowed down with the addition of numerous countries. However, he said, the addition of Japan last year was great news for Canada — given the potential for a "huge" increase in pork exports there.

"They want it to be an ambitious, high-quality agreement but they keep adding new players," he said. "It's proving to be a very interesting — but very complex — negotiation."

There are also believed to be huge differences over intellectual-property rules and environmental standards, although the negotiations are being conducted in secret.

That won't change with this week's developments one way or the other, said Kent Hughes, a scholar at the Wilson Center and former associate-deputy secretary at the U.S. Department of Commerce.

"There are still challenges in reaching a final agreement in the TPP," Hughes said.

"Having an actual agreement ready for signing and then submission to the Congress still is not near. We will have to keep our eye on the negotiations, but I think they can continue at a reasonable pace."

News from © The Canadian Press, 2014