Climate action advocates thanked Sen. Bernie Sanders for being adamant during Tuesday night's Democratic debate that climate and trade issues are one and the same, even as debate moderators attempted to separate the subjects.

When asked about the USMCA, which he voted against moving out of committee on Tuesday, Sanders said he would not support any trade deal that "does not incorporate very, very strong principles to significantly lower fossil fuel emissions in the world."

"Every major environmental organization has said no to this new trade agreement because it does not even have the phrase 'climate change' in it," the Vermont senator and 2020 presidential candidate said.

When Des Moines Register political reporter Brianne Pfannenstiel told Sanders that the debate would soon cover the climate crisis but the topic at hand was trade, the senator countered, "They are the same in this issue."

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Grassroots group the Sunrise Movement praised the senator for making clear the connection between the climate and trade.

The group, which endorsed Sanders last week, was among the climate action advocates praising the senator following the debate.

Sanders was joined by only three of his Democratic colleagues on the Senate Environment and Public Works Committee on Tuesday—Sens. Kirsten Gillibrand (D-N.Y.), Ed Markey (D-Mass.), and Sheldon Whitehouse (D-R.I.)—in voting against the USMCA. 

The lawmakers cited concerns over "special protections" for fossil fuel companies' profits, food safety regulation rollbacks, allowances for chemical companies to keep data about toxic pesticides secret, and other failures to mitigate the climate and ecological emergency, as reasons for opposing the deal.

In December, climate action groups including the Sierra Club and the Natural Resources Defense Council (NRDC) sent a letter to lawmakers imploring them to reject the USMCA because it "fails to meet the baseline standards for environmental and climate protection that the environmental community has consistently called for."

Food & Water Action called the deal "a one-way ticket to climate disaster" in a statement Wednesday.

"Elected officials in America are charged with protecting consumers against cheap and unsafe imported food, contaminated water, and public health threats," said Mitch Jones, the group's policy director. "USMCA ransacks protections on all three fronts."

"America needs a leader who will intervene on deals like this that could lead to our children eating contaminated deli meat," he added. "Every leader in this country, especially one who wants to be our president, must oppose USMCA in the name of a healthy future."