Bernie Sanders (D-Vt.) sat alone at an otherwise empty dais during today’s Senate hearing on Immokalee tomato pickers, asking questions he already knew the answers to.

For months, Sanders has campaigned alongside workers to expose exploitation in Florida’s tomato fields, where migrant laborers toil for a meager 45 cents for every 32-pound bucket of tomatoes they harvest and haul–a wage rate that, adjusted for inflation, has decreased by 75% over the past 30 years. Yet today even Sanders, once again hearing the extent of abuses in the fields, seemed hard-pressed to keep an expression of incredulity off his face. The Coalition of Immokalee Workers’ Lucas Benitez testified about seven-day workweeks, debt bondage, and armed crew bosses that beat workers who attempt to leave. Eric Schlosser–who’s written extensively about farm-labor sweatshops but describes conditions as such that nevertheless “defy words”–spoke of a culture of exploitation that allowed Abel Cuello, a man convicted in 1999 for enslaving at least 30 migrants in Florida and South Carolina, to readily find work again upon leaving prison with Ag-Mart Produce, one of Florida’s largest tomato growers.

After listening to the witnesses, Sanders continued to duly interrogate them. But what questions could he really ask? The issue the hearing highlighted–tomato pickers’ wages–could hardly be more unambiguous.

The back story is simple: In 2005, Taco Bell–dogged by a four-year consumer boycott led by CIW–agreed to pay an extra penny per pound for tomatoes it purchased. A small pittance for Taco Bell to give up, but the victory was real, granting workers their first significant pay raise in decades. And last year, those gains were solidified when McDonald’s signed onto the agreement as well, alongside Pizza Hut and KFC.

But in November, the Florida Tomato Growers Exchange–which represents 90 percent of the state’s growers–stepped in. Not only did they reject the agreement, but they also threatened a $100,000 fine against any grower who accepted extra payment for migrant wages. There’s no reason for this, since the agreement doesn’t actually cost growers. But as one grower explained his opposition to such worker concessions (and Benitez shared before the committee), “A tractor doesn’t tell the farmer how to run the farm.” Likewise in questioning today, FTGE’s Reggie Brown maintained the tomato growers’ line, declaring that he’d never heard of abuses like those his co-panelists (including a detective from the local county sheriff’s office) described.

There were few cameras at today’s hearing, and few of Sanders’ colleagues, either. But of course, the real action Sanders and the Immokalee workers hope for couldn’t happen in the hearing. Rather, theirs is the hope that the Southern Poverty Law Center’s Mary Bauer expressed in her testimony: “I do not believe American people would be silent if they knew how their food was being produced.” Or members of Congress, either.

Join Sanders and the CIW here.