WASHINGTON (Reuters) - U.S. House Democrats on Tuesday backed a renegotiated version of the U.S.-Mexico-Canada (USMCA) trade agreement after a year of often acrimonious negotiations with the White House, and it was signed by the United States, Canada and Mexico.

Mexico's President Andres Manuel Lopez Obrador, Canadian Deputy Prime Minister Chrystia Freeland and U.S. Trade Representative Robert Lighthizer pose next to other representatives during a meeting at the Presidential Palace, in Mexico City, Mexico December 10, 2019. REUTERS/Carlos Jasso

What must happen next to ensure the new trade agreement can go into force?

MEXICO

Mexico’s Senate passed the original USMCA earlier this year, and must now approve the modifications. The modified deal, which would replace the 1994 North American Free Trade Agreement, will be sent to Mexico’s Senate on Tuesday where it will be analyzed by committee chairs before going to a vote. The Mexican government has already gone over the changes in consultation with senators and the modified agreement should pass easily.

CANADA

The treaty has to be approved by both the elected House of Commons and the appointed Senate. That is a straightforward process and could be wrapped up in a couple of weeks if need be. The Canadian parliament is due to start its winter break on Friday, however, and legislators are not scheduled back until Jan. 27.

UNITED STATES

The revamped USMCA must be ratified by the U.S. Congress, a process that could stretch into January or February, after the expected impeachment trial of U.S. President Donald Trump.

The Democratic-controlled House of Representatives is ready to vote on the trade agreement and is confident it can win approval before the end of the year, lawmakers said on Tuesday.

The trade agreement must be voted on by the House Ways and Means Committee before it can go to the House floor, a perfunctory step expected to be completed quickly.

Congressional experts said the House would likely forgo a “mock markup” of the implementing legislation for the trade deal since its negotiators had already won substantial changes to the agreement. There could be some debate on the House floor.

Once brought to the floor, the trade agreement needs a simple majority to pass.

The measure must also be passed by a simple majority of the 100-member Republican-controlled U.S. Senate. But Senate Majority Leader Mitch McConnell said the trade deal would not be considered next week before the chamber begins its winter congressional recess.

McConnell said the Senate would likely address the trade deal after an impeachment trial, which could last through January or February.

The Senate Finance Committee could hold a hearing on the trade agreement, giving its members a chance to air concerns, since they had virtually no role in revising the initial version of the agreement, congressional sources said.