When ACORN took to Las Vegas and started playing "Blackjack" and "21," the activist group was making a far bigger gamble than it ever guessed, according to Nevada prosecutors.

There's nothing wrong with playing the tables in Vegas, but authorities say ACORN was using the names of those casino games as a cover to illegally pay workers to sign up voters as part of an illegal quota system.

A preliminary hearing Tuesday in the downtown Clark County courthouse has put ACORN on trial for the first time as a criminal defendant.

Until now, prosecutions for voter registration fraud have focused on ACORN workers, and authorities have secured guilty pleas from several who admitted to falsifying voter registration forms.

But when investigators from Nevada Secretary of State Ross Miller's office raided the ACORN Las Vegas office, Ross says they found a paper trail that implicated the ACORN organization itself.

"We came across policy manuals that outline their policy of creating a quota system, which is against the law," Miller told FOX News in an interview. "This, in fact, was something that was widespread and something the organization itself knew about, and it's important to hold the organization criminally accountable as opposed to the individual field directors."

ACORN denies it had a quota for the number of voter registration forms that its workers were required to turn in every day. Instead, the organization says there were "performance standards" — an expectation that workers would find 20 new voters a day.

But prosecutors say ACORN paid a $5 bonus per day to workers who would sign up 21 or more voters per shift, hence the name "21" or "Blackjack," an alleged quota system that Ross says is the first step toward corrupting the democratic system.

"These charges strike at the heart of having integrity of the electoral process. That's something that is important in Nevada and the entire country," he told FOX News.

"By filing these charges we are sending a clear message we are not going to tolerate these kinds of activities. We have seen voter registration abuse before and we are holding these people accountable."

Pressure has been mounting on ACORN in recent weeks after videotapes surfaced showing staffers in multiple cities offering advice to a man and woman posing as a pimp and a prostitute on how to commit tax fraud.

The IRS and Census Bureau have severed ties with the group, and the inspector general of the Department of Justice is reviewing the agency's involvement with ACORN. More than a dozen state and local authorities are also scrutinizing ACORN, including Maryland's attorney general.

ACORN lawyer Lisa Rasmussen told FOX News that the Nevada prosecution is "selective and has unfairly targeted ACORN." She claims the case violates the right to petition to gather voters.

At the preliminary hearing Tuesday, prosecutors and defense lawyers sparred over the arcane regulations of voter registration. But the highlight of the proceedings was the testimony of Christopher Edwards, the 33-year-old former ACORN field director who has cut a deal with prosecutors to testify against the group.

Edwards has begun to provide a view inside ACORN's operations, telling investigators about the Blackjack program in the Las Vegas office, which allegedly submitted the names of the starting lineup of the Dallas Cowboys as new voters.

"It's Las Vegas, it's blackjack," Edwards testified, describing what he called the "Blackjack bonus," saying ACORN set a quota of 20 cards per day for workers, and 1,000 a week for the group's political organizers. Edwards described a huge sign in the ACORN office that read: "Blackjack Bonus, 21 cards, extra 5 dollars," and said the program was instituted with the approval of higher-ups.

In fact, he said, other ACORN offices were jealous of the Blackjack program. Edwards said there were problems with payroll fraud at ACORN, noting that a Detroit voter registration director paid himself twice, falsely claiming he was also a canvasser.

Edwards told the court that he hired Nevada "non-violent offenders" from a prison transition facility as canvassers, and when asked if there was pressure from ACORN to increase voter registrations, he said, "every day."

If the trial goes forward and ACORN is convicted, the Nevada operation could lose its tax-exempt status. That would have national implications for the organization — meaning ACORN could end up with a losing hand.