Democratic presidential candidate Elizabeth Warren is facing criticism from climate advocates over her decision to back President Donald Trump s updated deal to replace the North American Free Trade Agreement, or NAFTA.

While lamenting that we really need trade negotiations going forward that make sure anyone who wants access to our markets is actually helping us in the fight against climate change, the Massachusetts senator said Friday that she will vote for the latest version of the agreement dubbed the United States-Mexico-Canada Agreement, or USMCA.

She had previously panned an earlier version of Trumps deal as NAFTA 2.0 and vowed to oppose it in the Senate, saying it wont stop the serious and ongoing harm NAFTA causes for American workers.

Its disappointing that a progressive and quite radical thinker as Elizabeth Warren has come out in support of this, said Manuel Perez-Rocha, an associate fellow at the Institute for Policy Studies and co-author of a report criticizing the updated deal s benefits to polluters.

The announcement marked a split with Warrens main progressive rival for the Democratic nomination, Sen. Bernie Sanders (I-Vt.), who said he opposed the deal during last months televised primary debate. (Sanders did grant that Trumps pending deal was a modest improvement over what we have right now.)

The final pact makes mostly small changes to the 26-year-old trade agreement, giving the U.S. more access to the Canadian dairy market, encouraging stricter labor laws in Mexico and tightening rules on auto manufacturers. The tweaks were enough to garner the support of some of NAFTAs biggest skeptics, including Sen. Sherrod Brown (D-Ohio), Rep. Rosa DeLauro (D-Conn.) and the AFL-CIO, the nations largest federation of unions. The Democratic-controlled House voted 385 to 41 last month to approve the deal.

But the new pact doesnt even mention climate change, and the final version includes provisions that make it cheaper to export Canadian tar-sands oil, give corporations more power to undercut Mexicos environmental policies and allow foreign companies to challenge proposed regulations in the U.S. or request the repeal of existing rules.

Its deeply concerning that Sen. Warren has reversed her stance on this, said Stephen OHanlon, a spokesman for the Sunrise Movement, an influential climate group pushing a Green New Deal. This trade deal is a huge win for fossil-fuel billionaires and for multinational corporations. It undermines her commitments to the Green New Deal.