They were encouraged to do so by labor leaders, who did not mention that an anti-TPP vote would embarrass President Obama — an argument that had succeeded in blocking anti-TPP language at the last meeting of the platform drafting committee. Instead, they said that the compromise language did plenty to blunt Republican efforts to run on trade.
"We take what Trump has used as a sound bite, and we turn it into a standard," said American Federation of Teachers President Randi Weingarten.
"The trade union movement does not take a back seat to anybody regarding its opposition to bad trade deals," said Lee Saunders, president of the American Federation of State, County and Municipal Employees and the sponsor of the compromise language.
Sanders's forces, in the committee and in rows of seats set up for non-voting spectators, found that case to be wanting. They made the campaign against the TPP the focal point of this weekend's debate, organizing delegates and representing the 800,000 anti-TPP signatures Sanders's campaign had obtained with stacks of cardboard boxes.
When it came time to fight, the Sanders forces tried two tactics. The first was an amendment to the compromise plank, tweaking it to say "and that's why we oppose the TPP." The second was a separate amendment that would have put the party on record against a TPP vote this year.
With 90 delegates supportive of Clinton, 72 supportive of Sanders, and 25 uncommitted to any candidate, they hoped that at least a few Clinton supporters would see the merits of opposing the TPP, a position Clinton herself came to adopt during the primaries.
“We’ve had no speech in favor of TPP, but we can’t bring ourselves to say that we oppose TPP?" asked an incredulous Robert Kraig, a Sanders delegate from Wisconsin.
Ben Jealous, the former NAACP president who introduced the brief amendment to the compromise language, argued that the Democratic Party would give away an electoral advantage if it was too slippery about trade. He warned that Republicans were likely to reflect Donald Trump's campaign rhetoric, and oppose the TPP in their own platform, creating an opening for the GOP — "a Republican opponent who intends to run clearly against bad trade deals" — that had never existed before.
"The majority of Democrats, like the majority of Americans, are against the TPP," Jealous said. "Hillary is against the TPP. Bernie is against the TPP. Let’s not be bureaucrats — let’s be leaders."
Jealous's amendment failed, winning just 74 votes, as cries of "shame!" and "you're giving Trump the vote!" arose from the back of the room.
"We all have to go home tomorrow and face our neighbors and tell them what we did to protect their jobs," said Carli Stevenson, a Sanders delegate and platform committee member from Indiana, who reminded the room of how powerful the trade issue had been there. "The best way to do that, and to leave no doubt, is to say that the Democratic Party opposes the Trans-Pacific Partnership."
The defeat of Jealous's amendment made it clear that the Sanders forces would lose on every trade question. Some of the observers turned their backs and held their thumbs down out of disgust for what had just happened.
"This is the Clinton campaign in a nutshell — surreptitious, and always with an agenda," said environmental activist Anthony Rogers-Wright. "I didn't really have much hope that the corporate wing of the Democratic Party would want to take a stand."
The vote on the amendment to deny any TPP vote in Congress went forward anyway. Jim Hightower, the progressive commentator and Sanders delegate from Texas, warned committee members that failing to go on the record would help Trump's campaign.
"He is gonna hammer Hillary mercilessly on the wimpy language in her platform," Hightower said. "I offer this amendment as a form of political viagra."
The Hightower amendment quickly went down to defeat, with 71 committee members in support and 104 opposed. A small group of observers then walked out of the room, yelling "sell out!" Richard Hillwig, who had come wearing a T-shirt with the Green Party's logo, said that the party had lost him for good.
"I voted for Obama twice, but I'm never voting for a corporate candidate again," he said.
Meanwhile, the presidential campaigns tamped down any suggestion of party division. Maya Harris, senior policy adviser for the Clinton campaign, said in a statement that Clinton "is not interested in tinkering around the margins with TPP," and believed that "the TPP fails the test that is now laid out in the platform."
The Sanders campaign expressed some disappointment but tried to portray the outcome as a partial victory.
"The good news is that virtually everyone who spoke during the debate on trade made it clear that they opposed this unfettered free trade agreement," said Warren Gunnels, Sanders's policy director. "Sen. Sanders, Sec. Clinton and the overwhelming majority of Democrats agree: The TPP should not come up for a vote after the election. If Democrats are going to prevail in November we must make clear to the American people that we stand firmly against the TPP. We will continue fighting to protect American jobs and to ensure Congress does not pass this disastrous trade agreement."
But many Sanders supporters see a way to revive the TPP fight at the convention. If just a quarter of delegates back a minority report from this weekend's meeting, it could earn a vote on the floor — a vote where many pro-Clinton members of Congress who oppose the TPP might face an awkward choice. The popular choice, Sanders supporters note, would be to oppose the trade pact.
"We're trying to save Secretary Clinton from herself," said Brent Welder, a labor lawyer and Sanders delegate from Missouri.