Before the Democratic Party's platform is finalized at a meeting late next week, Bernie Sanders and his progressive allies are mobilizing to ensure that opposition to the Trans Pacific Partnership (TPP)—described by its critics as a global corporate power grab—is made the party's official stance.

Though President Obama continues to lobby hard on behalf of the controversial deal, and despite a proposal to include such language being voted down during a drafting session last weekend in St. Louis, Sanders and his supporters are making their case into a rallying cry about the future of the Democratic Party.

On Wednesday, both the Sanders campaign and Democracy for America, a progressive advocacy group, launched petitions calling on the platform committee to include the anti-TPP language in the final version.

"The Democratic Platform includes a number of very important initiatives that we have been fighting to achieve during this campaign," reads the petition from the Sanders campaign. "But one big item is missing: preventing the disastrous Trans-Pacific Partnership trade deal from ever coming up for a vote in Congress."

In addition to citing the publicly stated opposition of both Sanders and Clinton, the Sanders petition points out how the TPP is also opposed by key Democratic voting blocs—including "virtually every labor union, environmental group, and even major religious groups." The party as a whole, the petition argues, should now "go on record in opposition to holding a vote on the TPP during the lame duck session of Congress and beyond."

According to DFA's petition, "opposition to the job-killing TPP should not be controversial within the Democratic Party: Both Bernie Sanders and Hillary Clinton campaigned against the TPP during this year's presidential primary."

Though many have questioned just how resolute Clinton will be in her opposition to the TPP, others are willing to take her at her word and argue that it is Obama and other pro-TPP forces within the Democratic Party who undermine her campaign by not falling in line. Either way, outside progessive forces have remained vigilant against the corporate-friendly agreement even as Obama steadfastly argues on its behalf.

Meanwhile, in a op-ed in the New York Times this week, Sanders warned the Democratic leadership they needed to "wake up" when it comes to recognizing just how frustrated working people and the poor are when it comes to an economic system that is so clearly rigged against them.

While the 15-member committee voted down the measure in St. Louis by a 10-5 vote—with the five Sanders-appointed members voting in favor and all the Clinton- and DNC-appointed members voting against—the split offers a window into how Sanders and the millions of voters inspired by his campaign hope to influence the party in the weeks and months ahead. In turn, the battle over TPP—as well as similar fights related to the minimum wage, climate action, and universal healthcare—will reveal much about how the party establishment, currently transitioning its leadership from Obama to Clinton, will respond to the groundswells from below.

As the Washington Post reports Thursday, members of the platform panel who voted to reject the anti-TPP proposal said it was influence coming from the White House, not their own feelings on TPP, which most impacted their decision.

Citing "people with knowledge of the platform negotiations," the newspaper reports how

Sanders used his post-primary meeting with the president to say he would push for the party to officially oppose the TPP. The president said he would now allow it. And since then, the White House has leaned on key Democrats to make sure that the platform did not include a rebuke.

This is how Rep. Elijah Cummings (D-MD), co-chair of the platform committee, explained his vote: "We have one president, and I have listened to him argue his case many times, and I know that he truly believes this. He really does. I disagree with him, but I don't want to do anything, as he ends his term, to undercut the president. I'm just not going to do it. In his last six months? I'm not gonna do that."

Sanders, however, appears very willing to challenge the president on the issue which he believes will so negatively impact the planet, people, and communities for generations to come.

"Well, I don’t want to embarrass the president either. He’s a friend," Sanders told USA Today in an interview this week. "But in a Democratic society, people can have disagreements."

And in a series of tweets that began Wednesday night and continued into Thursday morning, he made it clear that the fight over TPP is among the foremost issues on his mind:

Our job is to do everything we can to rally support for an amendment to the platform in strong opposition to the TPP. #StopTPP — Bernie Sanders (@BernieSanders) June 29, 2016

Tell the DNC: We have gotta strongly oppose bad trade agreements like the TPP in the Party Platform. #StopTPPhttps://t.co/PdXXerIGt0 — Bernie Sanders (@BernieSanders) June 29, 2016

The TPP is a continuation of our disastrous trade policies that have devastated manufacturing cities all over this country. #StopTPP — Bernie Sanders (@BernieSanders) June 30, 2016

We need trade policies that benefit American workers, not just corporate CEOs. Democrats must do all they can to defeat the TPP. #StopTPP — Bernie Sanders (@BernieSanders) June 30, 2016

Trade is a good thing but it has to be fair. And the TPP is anything but fair. We must ensure the TPP doesn't come up for a vote. #StopTPP — Bernie Sanders (@BernieSanders) June 30, 2016

The question, however, remains. If a majority of the Democrats on the panel oppose the TPP and the presumptive nominee opposes the TPP and the challenging candidate who won 22 primary contests by stirring the hopes of millions of voters opposes the TPP, why can't the leadership of the DNC take this opportunity to recalibrate the trajectory of the party on this seminal issue?

The full Democratic Platform Committee will meet in Orlando on July 8th and 9th to approve the final draft of the platform.