Republican Donald Trump and Democrat Bernie Sanders's smashing victories in the New Hampshire primary on Tuesday have complicated the path for US Congress to approve the controversial Trans-Pacific Partnership (TPP) deal this year, with the booming anti-trade fervor haunting the 2016 presidential campaign.

Having long been regarded as outsider candidates in both parties, Trump and Sanders are railing against the Pacific trade deal between the United States and 11 other Asia-Pacific countries, a top legislative priority for the Obama administration this year, in their presidential primaries.

Sanders, the Independent senator from Vermont and a longstanding opponent of international trade, said that he would not sign this "disastrous free trade agreement" into law if elected president of the United States.

"I think it is a continuation of bad trade policies. The president supports it, I strongly disagree with it," Sanders said at a town hall meeting in New Hampshire last Wednesday, arguing the TPP mainly reflected corporate interests and could "throw American workers out on the street."

Former Secretary of State Hillary Clinton, Sander's rival for the Democratic presidential nomination, also reiterated last week that she would not support the TPP in its current form and would seek changes to the trade pact if elected.

"I do not currently support it as it is written," Clinton said during a televised debate last Thursday. "There are changes I believe that would make a real difference, if they could be achieved."

Clinton has previously said she doesn't believe the current TPP deal would meet her "high bar" for creating good American jobs, raising wages and advancing national security, citing the failure of the trade agreement to address currency manipulation and pharmaceutical provisions.

On the Republican side, Donald Trump, the billionaire developer and GOP front-runner, and Ted Cruz, the conservative senator from Texas and the winner of the Iowa caucuses, have both spoken out against the TPP deal.

Florida Senator Marco Rubio, who was widely regarded as a potential alternative to Trump and Cruz by establishment Republicans, has said he will not reveal how he will vote on the trade deal until May 18th or later. Rubio's refusal to take a firm position on the TPP reflects the fact that American voters are not enthusiastic about free trade during the primary season.

During a closed-door meeting at the White House last week, President Barack Obama discussed the TPP with House Speaker Paul Ryan and Senate Majority Leader Mitch McConnell, but failed to reach a deal on the precise timing of congressional vote on the trade pact.

While the Obama administration urged Congress to approve the TPP deal as soon as possible, McConnell reiterated that the administration should not submit the trade deal to Congress for a vote before the presidential election in November.

"With both the Democratic candidates for president opposed to the deal and a number of presidential candidates in our party opposed to the deal, it is my advice that we not pursue that, certainly before the election," McConnell told reporters after the meeting, adding that the deal has a number of flaws that need to be addressed.

Major influential US business groups, including the US Chamber of Commerce, the National Manufacturers Association and the Business Roundtable, have expressed their disappointment over provisions governing tobacco, pharmaceuticals and financial institutions in the TPP deal, which was formally signed by ministers from its 12 member countries in New Zealand last week after more than five years' negotiation.

The TPP will now undergo a two-year ratification period in which at least six countries, which account for 85 percent of the combined gross domestic production of the 12 TPP countries, must approve the final text for the deal to be implemented.

The 12 countries include Australia, Brunei, Canada, Chile, Japan, Malaysia, Mexico, New Zealand, Peru, Singapore, the United States and Vietnam.

Senate Finance Committee Chairman Orrin Hatch, who has particular concerns about provisions related to duration of intellectual property protections for biologic drugs, signaled the TPP might face a long delay between the signing and final congressional approval.

"If history has taught us anything, it's that this process can, and often does, take a very long time to complete," Hatch said on the Senate floor last Wednesday. "In fact, it's not an exaggeration - or even all that remarkable - to say that it can take years to get an agreement through Congress after it is signed."

Hath noted that the US free trade agreements with Colombia, Panama and the Republic of Korea were not approved by Congress until more than four years after they were signed.

Ryan also predicted that there are not yet enough votes in Congress to pass the TPP deal. "There are enough concerns about this agreement, some that I also have, where I don't see enough support for it right now," Ryan said Tuesday in an interview with the Journal Times, the local newspaper in Racine County, Wisconsin.