More than two-thirds of New York’s delegation to the House of Representatives signed onto a letter calling for President Barack Obama to abandon the central plank of his trade agenda—the sprawling Trans-Pacific Partnership.

The group of six Republicans and 13 Democrats pointed to the evaporation of some 370,000 factory jobs since mid-90s, when the U.S. joined the North American Free Trade Agreement and the World Trade Organization. The TPP would ease trade barriers and a host of regulations between the United States, Australia and several Asian and Latin American nations—and the pols feared that it could result in the outsourcing of even more low-skilled positions.

“Like many Americans, New Yorkers have grown increasingly disillusioned with our nation’s international trading relationships and are rightly skeptical that the TPP will fare better than previous trade agreements,” the group wrote to Mr. Obama.

The representatives hail from all parts of the city and state, from Buffalo-area Congressman Chris Collins to Congressman Lee Zeldin of Suffolk County, from Bronx Democrat Jose Serrano to Staten Island Republican Daniel Donovan. One signatory, upstate GOP Congressman Chris Gibson, is considering challenging Gov. Andrew Cuomo in 2018.

They shared the concern that the TPP does not do enough to address the deliberate devaluation of foreign currencies, which makes products manufactured overseas cheaper for American consumers and U.S.-produced goods more expensive for buyers abroad. The representatives noted that TPP participants like Japan, Malaysia and Singapore have induced inflation in their nations in order to gain such an advantage for their home industries.

“Currency manipulation is one of the greatest issues facing American manufacturers today and is estimated to have suppressed millions of U.S. jobs,” the members wrote. “The lack of meaningful currency provisions makes the TPP incomplete at best and destructive to domestic manufacturers at worst.”

Supporters of the TPP insist that a similar agreement will inevitably emerge with or without American participation, possibly with China or Japan setting the terms instead of the U.S. The White House did not respond to requests for comment, but Mr. Obama called upon Congress to pass the agreement this year.

The president, with the help of the GOP House majority, obtained so-called “fast track authority” last summer. This granted him the power to negotiate the pact unilaterally, and only allows Congress to vote in favor or against it, and denies it the power to alter individual terms of the deal.

The treaty has featured heavily in the 2016 presidential race. Vermont Sen. Bernie Sanders, the Democratic underdog, and developer Donald Trump, Republican front-runner, have made their opposition to the pact a centerpiece of their campaigns.

Hillary Clinton, the former secretary of state, was instrumental in orchestrating the accord—but has since repudiated it. Because of the controversy, many expect the administration will seek a vote on it during the “lame duck” session following the election.

The TPP does have supporters in New York, including Queens Congressman Gregory Meeks and Nassau County Congresswoman Kathleen Rice, both Democrats. Besides Mr. Meeks, Queens Congressman Joseph Crowley and Harlem Congressman Charles Rangel were among the eight New York representatives not to sign the letter to the president, though both opposed granting him fast-track authority last year.

Read the full text of the letter below:

Dear President Obama: New York State is home to the best workers and some of the most innovative companies in the world. As bipartisan Congressional Representatives of the people and businesses of New York, we write to express our firm opposition to the Trans-Pacific Partnership (TPP) as negotiated. Like many Americans, New Yorkers have grown increasingly disillusioned with our nation’s international trading relationships and are rightly skeptical that the TPP will fare better than previous trade agreements. In the months since the TPP’s text was released to the public, we have made a careful review of its wide-ranging provisions. Our concerns with the TPP are as varied as the people and districts we represent, but there are a number of core issues with the agreement that we all share. Since the North American Free Trade Agreement (NAFTA) and the World Trade Organization (WTO) agreements took effect in 1994, our state has lost more than 370,000 manufacturing jobs. This is just a portion of the five million manufacturing jobs that have been lost nationwide over that period. While we recognize the difficulty in proving a causal connection between trade agreements and job losses, the federal government itself has certified more than 115,000 New York jobs under the Trade Adjustment Assistance (TAA) program as having been lost to imports or off-shoring since NAFTA. TAA only covers a subset of jobs displaced due to trade, so this figure represents only a fraction of New York job losses directly attributable to trade agreements. Glaringly, this TPP agreement has no effective measures to address currency manipulation. Currency manipulation is one of the greatest issues facing American manufacturers today and is estimated to have suppressed millions of U.S. jobs. Japan, Malaysia, and Singapore each have histories of artificially controlling their currencies, yet the TPP provides no enforceable protections against their doing so. The side declaration on currency practices is insignificant, unenforceable, and does little to assuage our concerns. The TPP is the United States’ best chance to address currency manipulation in a systematic way, and the lack of meaningful currency provisions makes the TPP incomplete at best and destructive to domestic manufacturers at worst. Given a level playing field, New York workers and businesses can compete and win in the global marketplace. While we each have our own concerns with the Trans-Pacific Partnership, we are united in our opposition to the agreement and in our belief that the TPP will harm many working and middle-class families in New York and across the country. Sincerely, Chris Collins, Member of Congress

Louise M. Slaughter, Member of Congress

Yvette D. Clarke, Member of Congress

Daniel M. Donovan, Jr., Member of Congress

Eliot L. Engel, Member of Congress

Christopher Gibson, Member of Congress

Brian Higgins, Member of Congress

Hakeem Jeffries, Member of Congress

John Katko, Member of Congress

Nita M. Lowey, Member of Congress

Carolyn Maloney, Member of Congress

Sean Patrick Maloney, Member of Congress

Grace Meng, Member of Congress

Jerrold Nadler, Member of Congress

Tom Reed, Member of Congress

José E. Serrano, Member of Congress

Paul Tonko, Member of Congress

Nydia Velázquez, Member of Congress

Lee Zeldin, Member of Congress

Disclosure: Donald Trump is the father-in-law of Jared Kushner, the publisher of Observer Media.