"It's about powerful people taking the public's money and using it to expand and enhance their campaigns," Chief Deputy Attorney General Frank Fina told the jury of six men and six women in Dauphin County Court.
Three people are facing trial, including former State Rep. Brett Feese and Brian Preski, formerly Perzel's chief of staff.
Once one of the most powerful people in Pennsylvania politics, Perzel was initially charged in the case but pleaded guilty this month to conspiracy and other charges. He is expected to be the prosecution's star witness, detailing how he and others allegedly conspired to tap upward of $10 million in public money to buy sophisticated computer programs that were then used to help win campaigns for Republicans.
The programs had catchy names, like the Edge and Candidate Connect. They allowed certain House GOP caucus members to mine specialized data on voters - everything from where they shopped for groceries to whether they owned a gun - to tailor campaign literature, Election Day tactics, and other campaign activities.
Attorneys for the defendants insisted that it was Perzel who drove the process, and that his hunger to amass power made him greedy and, ultimately, criminally responsible.
Perzel's attorney, Brian McMonagle, could not be reached for comment late Monday.
In his opening statement, Preski's attorney, Bill Winning, argued that the case was about Perzel and his "insatiable, never-ending quest for power."
"Brian Preski is not a criminal, is not a thief, did not steal any money from the taxpayers of Pennsylvania," Winning said. "And he is not criminally responsible for what happened."
Joshua Lock, Feese's lawyer, similarly contended that only a "select, secretive, almost manipulative group of people knew what was going on."
The third defendant in the case, Jill Seaman, "was a secretary, she didn't decide anything," said Bill Fetterhoff, her attorney.
Fina argued that while Perzel was the ultimate power broker, he needed - and had - right-hand and left-hand staffers. Preski was the right hand, Feese and others were the left, he alleged.
The prosecutor also detailed how the computer programs helped in campaigns. They tracked how voters felt about a specific Republican candidate, he said. They enabled campaign workers to follow who showed up at the polls, and how those people felt about the candidate the GOP was supporting.
And, Fina said, if that candidate's supporters weren't showing up to vote, the programs would alert the campaign workers to that as well. That, in turn, would allow a campaign to fan out and transport to the polls those voters who could help them win.
Taxpayers, Fina said, got the bill.
The trial is expected to last eight weeks. Ten people were originally charged; six, including Perzel, have pleaded guilty. The remaining defendant, former Perzel aide John Zimmerman, is expected to be prosecuted separately later this year.
Computergate grew out of the attorney general's "Bonusgate" investigation into how people connected to the House Democratic caucus used taxpayer money to reward employees who did political work.
Contact staff writer Angela Couloumbis at 717-787-5934, firstname.lastname@example.org or @AngelasInk on Twitter.