The risk for Democrats is that Trump may follow through on his threat to withdraw from the original NAFTA, a scenario that would increase tariffs across the continent.

Both parties realize the economic importance of getting the agreement approved, said Clete Willems, a former senior White House trade official who is now a partner at Akin Gump Strauss Hauer & Feld LLP in Washington. “I hope that both sides will put politics aside and get this passed,’’ he said. U.S. Trade Representative Robert Lighthizer, who led the re-negotiation of NAFTA, and Pelosi “are professionals.”

It “would be a sad commentary on the state of our affairs’’ if Pelosi and her caucus reject USMCA because Democrats don’t want to give Trump a win for 2020, Marc Short, Vice President Mike Pence’s chief of staff, said Wednesday. Pence is in Ottawa Thursday to advance the deal, which the Canadian and Mexican legislatures also still need to pass. Canadian Prime Minister Justin Trudeau on Wednesday introduced legislation to ratify USMCA.

Pelosi is not rushing congressional consideration because she needs to balance a wide diversity of views on trade in her caucus.

Trade skeptic Rosa DeLauro of Connecticut on Thursday said Canada was acting prematurely.

“While the Canadians rush to approve this deal, Congressional Democrats remain committed to making key changes to the core of the agreement that will include strong labor and environmental standards and enforcement and remove the monopoly rights for Big Pharma," she said.

House Democrat Gregory Meeks of New York, a member of the pro-trade New Democrat Coalition, said Pelosi has repeatedly consulted moderates about working out a deal on USMCA and refining Democratic demands.

"People want to get this done and realize that having an agreement is better than having no agreement," he said.

2020 Elections

The administration is encouraging U.S. lawmakers and businesses to lobby Pelosi’s office “to ask her to bring this forward for a vote in Congress because we think we have the votes,” Short said on CNBC.