Democratic lawmakers and liberal groups have called for decades for the North American Free Trade Agreement to be dropped or at least renegotiated, but when the Trump administration formally announced Thursday that it was opening talks with the Mexico and Canada, many reacted with pointed criticism of the White House.

The response highlights an awkward political situation for trade critics: Many want NAFTA scrapped but don't want Trump to get any credit for doing it.

The trade critics said that Trump, long before any negotiations have begun, has given every indication that he would sell out to international business. "The president's vague NAFTA letter is a stark contrast with the aggressive promises he made to hard-working families during the campaign. For all his rhetoric, President Trump looks to be sorely disappointing American workers on trade," said House Minority Leader Nancy Pelosi, D-Calif.

A few Democrats, however, indicated a second reason for their criticism: They are worried that Trump may steal the anti-trade issue away from them. "We had Trump come into our districts and talk tough about trade," said Rep. Mark Pocan, D-Wis., during a press conference Thursday.

Several other lawmakers made the same point: Trump assailed NAFTA and other trade deals during the 2016 election and that enabled him to make inroads into Democrat-friendly Rust Belt states in the Midwest. "We don't need pollsters to tell us this. We know why Trump is president of the United States," said Rep. Marcy Kaptur, D-Ohio.

Rep. Debbie Dingell, D-Mich., said that NAFTA is extremely unpopular in her district and she saw early the impact Trump's rhetoric against it had on the voters there. "I am one of those people who said that Donald Trump could become president because I saw how people in the Midwest felt." She added later, "He won by going through the Midwest and talking about trade."

That partly explains the almost-hostile reaction from many of NAFTA's staunchest critics to the news that the administration wants to renegotiate it. Many expressed concern that the headlines about reopening the talks would themselves constitute a political win for Trump, regardless of the details of any final agreement. "Trump's objective is to change as little as possible with NAFTA and to claim the biggest possible changes. He will seek something visual he can visit" for a photo opportunity, said Rep. Brad Sherman, D-Calif.

Democrats also said they needed to be given a prominent role in the renegotiations. "If they are going to do anything meaningful, they are going to need Democrats," said Rep. Pete DeFazio, D-Ore. The Democrats expressed irritation that Trump took credit for killing the Trans-Pacific Partnership trade deal earlier this year, arguing their efforts to derail the Obama administration's efforts to pass it were the real reason it died.

The critics argued that there were sound reasons to doubt that administration's efforts would improve the trade deal. They noted that Trump had campaigned on declaring China to be a currency manipulator and then backed away from that once in office. Several pointed to reports that Trump's personal business empire contains investments in Canada and Mexico. They said transparency was needed to be sure that Trump does not personally benefit from a renegotiation.

Rep. Rosa DeLauro, D-N.Y., said that many were concerned that Commerce Secretary Wilbur Ross, who leans toward free trade, will have a larger role in the negotiations than U.S. Trade Representative Robert Lighthizer, a NAFTA critic. "I, from the outset, have not known who is really in charge," DeLauro said.