WASHINGTON — The Democratic leadership of the House of Representatives on Dec. 10 declared support for the U.S.-Mexico-Canada Agreement (U.S.M.C.A.), clearing the way for a vote in the House. Should the House approve the agreement, it was expected the Senate will ratify the successor treaty to the North American Free Trade Agreement and that President Donald Trump will sign the measure into law, perhaps before the end of the year.

House Democrats signed on to the agreement after securing changes to the pact relating to enforcement, stronger labor rules, which mostly aimed at ensuring Mexico reforms its labor policies, enhanced environmental rules and prescription drugs.

“Today’s agreement is the culmination of months of House Democrats’ work to transform the new NAFTA into a deal that respects the dignity of workers, contains meaningful enforcement provisions and prioritizes environmental protection and remediation,” said House Ways and Means Committee chairman Richard E. Neal of Massachusetts. “Our purposeful efforts produced changes to the U.S.M.C.A. that earned the endorsement of the AFL-CIO and will set a new standard for U.S. trade agreements moving forward.”

Farm and agribusiness organizations rallied to the agreement and urged prompt congressional action.

Randy Gordon, president and chief executive officer of the National Grain and Feed Association, said, “We particularly appreciate the dedication and persistence of U.S. Trade Representative Robert Lighthizer and House leaders to overcome final hurdles on labor enforcement to reach this milestone. We also commend the governments of two of our most important trading partners — Mexico and Canada — in working with the United States to accommodate these concerns.

“We urge the House to expeditiously pass this agreement so it can be ratified by the Senate this year. Doing so will be a tremendous win for the United States and the entire North American region and our interdependent economies.”

The N.G.F.A. said the U.S.M.C.A. will preserve or expand market access for U.S. agricultural products in the North American market. In addition to maintaining a tariff-free environment for most agricultural goods, the U.S.M.C.A. will help address non-tariff barriers.

The N.G.F.A. said among other benefits, the U.S.M.C.A. will: facilitate cross-border trade flows through higher levels of regulatory coherence and cooperation, implement timelines and notifications for adverse import checks, include steps to reduce the likelihood of trade disruptions in products of agricultural biotechnology, use technical consultations for sanitary and phytosanitary (S.P.S.) disputes, and require that S.P.S. standards be grounded in science and based on risk assessments and implemented using accepted risk management techniques.

“Today’s announcement brings us one step closer to ratifying this important agreement and securing the future of our trading relationship with Mexico and Canada, the top export markets for U.S. corn farmers,” said Kevin Ross, president of the National Corn Growers Association. “It’s been a brutal year for many farmers who really need the certainty this would provide for agricultural trade.

“N.C.G.A. appreciates the bipartisan efforts between Speaker (Nancy) Pelosi, Ambassador Lighthizer and the House working group to reach an agreement. I urge lawmakers to pass U.S.M.C.A. and help us close out 2019 with a win for America’s farmers and the U.S. economy.”