White House hopeful Sen. Bernie SandersBernie SandersOvernight Finance: Trump takes US out of Pacific trade deal | WH says Trump has left his businesses | Lobbyists expect boom times The Rockefeller scheme to attack Exxon Mobil AT&T beefs up lobbying after merger proposal MORE (I-Vt.) called on Democratic presidential frontrunner Hillary ClintonHillary Rodham ClintonTrump told leaders 'illegals' cost him popular vote Trump continues to insist voter fraud robbed him of popular vote Xavier Becerra confirmed as California attorney general MORE to oppose the controversial free-trade agreement the Obama administration is negotiating with 11 Pacific nations.

Congress is currently considering legislation that would make it easier for the White House to complete its emerging deal, known as the Trans-Pacific Partnership (TPP).

“I would hope very much that Secretary Clinton will side with every union in this country, virtually every environmental group, many religious groups, and say that this TPP policy is a disaster, that it must be defeated, and that we need to regroup,” he said during an interview Sunday on CBS’s “Face the Nation.”

Sanders, who is running in the Democratic primary, has been a staunch opponent of legislation that would make it easier for the administration to complete the negotiations.

“I'm not saying trade is the only reason, but it is a significant reason why Americans are working longer hours for lower wages, and why we have seen our jobs go to China and other low wage countries,” he said.

The House dealt the White House a stinging blow on Friday, refusing to advance the legislation that would aide President Obama's negotiations.

Sanders voted against the Senate’s companion measure, which was approved in May.

He said Sunday that the House vote showed growing momentum against the TPP deal, which will be kept secret until it is completed.

“Don't you think it's a little bit silly for members of Congress to be voting yes on a bill that they haven't seen?” Sanders said. “That is one of many reasons to be voting against this piece of legislation.”

The Vermont senator wants Clinton to be more forceful in her stance on U.S. trade policy, which he believes benefits the wealthy at the expense of the middle class.

“Our trade policy has been for many years is to allow corporate America the shut down plants in this country, move abroad, hire people for pennies an hour, and then lead their products back into the United States,” Sanders said. “It is a failed trade policy, and I would hope that the Secretary joins Elizabeth Warren … and vast majority of Democrats in the Congress in saying, ‘No, we've got to defeat this piece of legislation.’”