As Hillary Clinton prepares to accept the Democratic nomination for president on Thursday night, labor unions are ready to demand that she put an end to the Trans Pacific Partnership (TPP)—a longstanding point of contention for her campaign.

Publicly shutting down the controversial 12-nation trade deal could keep lawmakers from introducing it to U.S. Congress in the lame duck session, which Clinton has said she opposes and which her former rival Sen. Bernie Sanders (I-Vt.) has said would be "going against the will of the people." Moreover, it would require breaking with President Barack Obama, who supports it.

And that's exactly what union leaders are looking for.

"I would like for her to finish this whole debate about TPP, that would be very important for us. I would like for her to articulate who she will be as president as the United States," Dennis Williams, president of United Auto Workers, told The Hill on Thursday.

The final push in the labor movement's anti-TPP campaign comes amid a week of controversy over Clinton's position on the trade deal. Although the former secretary of state has said she opposes the deal, her longtime ally Virginia Governor Terry McAuliffe indicated several times that Clinton would support it if certain changes were made.

On Thursday, McAuliffe clarified his comments for the third time, telling a closed-door meeting of Democratic National Convention (DNC) delegates that "Hillary is against TPP and she is always gonna stay against TPP. Let me be crystal clear about that."

But unions are still waiting to hear it from Clinton. Robert Martinez, president of the International Association of Machinists and Aerospace Workers, told The Hill, "I'd like to hear her come out and say she's strongly against trade deals like the Trans Pacific Partnership."

The Hill continues:

Unions feel they have strong leverage this week as the Clinton campaign has made it a top priority to win over liberals allied with her primary rival, Sen. Bernie Sanders (I-Vt.), and many of them also feel strongly about killing the TPP. They have met with lawmakers and delegations from across the country to ensure there aren't any Democratic defections after the election in case Republican leaders try to bring the trade deal to the floor in December.

"Lots of them—House members, Senate members, governors—I've met with the delegations and the delegations are doing the same. We've armed them with the facts and they're going out to their [Senate and House] members," AFL-CIO president Richard Trumka told the outlet.

Delegates and voters allied with Sanders were disappointed with Clinton's choice of a pro-TPP vice president, although Virginia Sen. Tim Kaine has come out against the deal since being tapped. Others noted that he also supported anti-union legislation while serving as governor of Virginia from 2006 to 2010.

Trumka sought to assure skeptics that Kaine would follow Clinton's lead on the trade deal, stating, "I know where Hillary's at and I know where Tim Kaine's going to be at. Tim Kaine's going to be right where the president's at," he said. "All she's got to say is what she's been saying: She's against TPP."

But that wasn't enough for many people feeling disillusioned with the 2016 election, which has been rife with conflict between progressive and establishment Democrats. As Dave Johnson writes at Campaign for America's Future, "Here's the thing. It doesn't matter whether Clinton, Kaine and others oppose TPP and globalization in their hearts. What matters is what they will do. They are more and more on the record, even it if is only that they want to win. This puts more and more pressure on them not to support TPP vote after the election."

To that end, the activist group MoveOn launched a petition calling on Clinton and Kaine to "clarify and amplify their opposition to the TPP, including in their speeches at the DNC."

On Wednesday, as Obama addressed the convention, numerous delegations waved massive signs with the letters "TPP" enclosed in a red circle with a line slashed through it. Closer to the stage, others unfurled a banner that read, "TPP Kills Democracy."