In the biggest courtroom of Chicago's Dirksen Federal Building Thursday, attorneys sat shoulder to shoulder and there were no empty seats.
Nine judges filed into the court for an unprecedented hearing to examine whether the Bureau of Alcohol Tobacco and Firearms had unfairly targeted blacks in undercover sting operations in Chicago and across the United States.
In those operations, cooperating witnesses, known as CI's, helped identify potential targets supposedly willing to take part in home invasion robberies of drug stash houses. The targets were encouraged by undercover agents to recruit a robbery crew, with the entire group arrested before they could travel to the stash houses, which turned out to be non-existent.
"Realistically, the overwhelming majority of the individuals that are selected are people of color," says defense attorney Richard Kling. "And certainly there are people who are white who are in gangs and are the type of people that the ATF are looking for."
Defense expert Jeffrey Fagan of Columbia University, testified that his analysis of a universe of nearly 300,000 potential targets in the Chicago area, indicated a far lower percentage of minorities than end up being targeted in the stash house operations.
The likelihood of that happening by accident, he argued, was virtually zero.
"In this district, the program swept up not the worst of the worst," University of Chicago Law Professor Allison Siegler wrote. "But enormous numbers of poor and vulnerable black people and other people of color."
Indeed, defendant David Flowers, watching from the gallery, suggested some residents of those neighborhoods amounted to low-hanging fruit for ATF agents anxious to make arrests.
"It's a rundown area," he said. "You give anyone an opportunity to see millions of dollars when they never had hundreds, they'll risk their life for it."
Fagan suggested he had run the numbers multiple ways, always reaching the same conclusion.
"It's my conclusion there's statistically significant evidence of discrimination," he said. "Even after we account for alternative explanations, we still find a pattern of discrimination."
But the government said Fagan's study was flawed, including thousands of individuals in his pool of eligibles who would never actually be willing to commit such crimes.
"ATF agents do not compile a list of citizens with criminal records throughout the district, select people from the list at random, and then cold-call those people and offer them a chance to rob a stash house," prosecutors wrote. "There is no reason the home invasion defendants should resemble professor Fagan's fantasy home invasion lottery."
Indeed, government expert Max Schanzenbach testified that only 37% of Fagan's huge pool of potential criminals had actually demonstrated a tendency to commit violent crimes. The larger group, he said, were filled with far too many who had only been convicted of simple drug or weapons charges.
"It includes people who are unavailable to the ATF," he said. "Or unwilling to commit stash house robberies."
At times, the hearing took on an almost surreal quality. To the right of the sprawling courtroom, twelve defendants in jumpsuits and shackles watched with varying levels of interest.
But some judges seemed openly skeptical of the defense team's arguments.
"You know what Mark Twain said about statistics," said Judge Robert Gettleman, noting Twain's famous observation, "There are lies, damned lies, and statistics."
The hearing continues Friday. The judges, who all have individual cases before them, are expected to take the matter under advisement and rulings are not expected until early next year. But the proceeding has legal implications impacting scores of cases which could be felt across the United States.
"Whether the government takes the case to the Supreme Court, I don't know," Kling said. "If the defense loses the case, I think it will end up in the Supreme Court."