After Never Trump Sen. Ben Sasse (R-NE) revealed on Thursday that President Donald Trump is exploring rejoining the Trans-Pacific Partnership (TPP) agreement, Sen. Bernie Sanders (I-VT) said doing so would “be a betrayal of American workers.”

“In a series of broken promises Trump made to the working people of this country, rejoining the job-killing Trans-Pacific Partnership would be the biggest yet,” Sanders tweeted. “Rejoining the TPP would be a betrayal of American workers and a step in the wrong direction.”

Sanders and Trump both opposed the TPP deal during the 2016 election cycle, and many working-class Democrats who voted for Sanders in the Democratic primary supported Trump in the general election because of the trade issue. In 2016, Sanders and Trump called out Hillary Clinton for waffling on the trade deal that she once referred to as the “gold standard.”

In fact, Trump said at a White House millennials event last month that support from Sanders supporters was instrumental in his victory over Clinton.

“I got a lot of Sanders voters,” Trump said. “That was a big part of the difference between Hillary Clinton and myself.”

Labor leader Richard Trumka, who recently praised Trump for his China tariffs, added that TPP “was killed because it failed America’s workers and it should remain dead. There is no conceivable way to revive it without totally betraying working people.”

As Breitbart News noted, Hillary Clinton’s top adviser, Philippe Reines, also admitted after the 2016 election that Trump’s opposition to the TPP agreement was a “big factor” in Clinton’s loss.

MSNBC host Ari Melber asked Reines last year, “Was trade and TPP a big factor in her loss? Yes or no?”

Reines responded: “Absolutely yes.”