While most Democrats vying to defeat President Donald Trump in 2020 have criticized his protectionist trade policies and trade war with China, Warren and Sanders have both said they are open to using tariffs in some ways.
And while Democrats and Republicans alike have championed the U.S. Mexico Canada Agreement, or USMCA, as a beneficial update to the North American Free Trade Agreement, Warren and Sanders have been more critical of it.
Still both carved out distinctions between their policies on the debate stage Tuesday night. Warren has said she would vote to approve the USMCA.
Sanders, asked about the Trump-brokered deal, said he would refuse to back the trilateral trade deal, despite previously saying it made some "modest improvements."
"We can do much better than a Trump-led trade deal," Sanders said, claiming that USMCA will exacerbate job loss through outsourcing.
Sanders also noted the lack of support for the deal from environmental organizations. "Every major environmental organization has said no to this new trade agreement because it does not even have the phrase 'climate change' in it."
"I will not vote for a trade agreement that does not incorporate very very strong principles to significantly lower fossil fuel emissions in the world," he said.
Warren began by touting her populist bona fides, saying she had opposed prior trade deals.
"But we have farmers here in Iowa who are hurting," she said, "and they are hurting because of Donald Trump" and his trade wars.
The USMCA, she said, "will give some relief" to U.S. farmers and workers: "I believe we accept that relief, we try to help the people who need help, and we get up the next day and fight for a better trade deal."
Sanders responded that retooling existing trade deals is no easy task. "I believe if this deal is passed, it will set us back a number of years," he said.