Colin Robertson, a former Canadian diplomat based in Washington who is now vice president of the Canadian Global Affairs Institute, said that because American unions are pleased with several parts of the U.S.M.C.A., the Democrats are not likely to block the agreement.
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Canadians will also closely watch the tariffs that Mr. Trump imposed this year on steel and aluminum exports to the United States.
Many Canadians were offended Mr. Trump had argued that the Canadian products were a threat to Americans’ national security. And while Mr. Trump made comments suggesting that the tariffs would be lifted once the previous trade deal, the North American Free Trade Agreement, was renegotiated, that has not happened.
Congress does not have direct control over tariffs, so it is unclear whether the Democrats could influence them.
But the change in congressional power could effect climate change policy and environmental law.
When Mr. Trudeau came to office in 2015, he made climate change one of his top priorities and swiftly moved to work with the Obama administration on the subject. Mr. Trump has since unwound many of those measures.
Mr. Trudeau is now working to keep Canada’s national carbon pricing program intact after some provinces refused to participate or withdrew from it. Critics argue that taxes on emissions from Canadian industries put them at a competitive disadvantage with their American counterparts, though Mr. Trudeau’s system makes allowances to prevent that.
It’s likely, Professor Rowlands said, that the House will fight any further environmental rollbacks by the Trump administration. Still, he said, he doubted it would be able to reverse the many significant changes it has made to date.
“The view here is that the House will be able to contain some of the things the administration has done that, from a Canadian perspective, have been a disaster,” he said.