DES MOINES -- Federal prosecutors told an Iowa jury today that former congressman Ron Paul will be called as a witness in a case against former campaign staffers who allegedly falsified finance reports as they paid a state senator for his endorsement. The government's case, presented in opening arguments today, describes the three-time presidential candidate as a sort of casualty of a scheme he never approved.

"Ron Paul wanted his campaign to be about ideas," said Richard Pilger, an attorney for the Justice Department. "He hated the idea of endorsements. He'll tell you that in his career, he only sought one endorsement -- from Nolan Ryan."

The trial, which is expected to last into next week, pits federal investigators against former Paul campaign chairman/spokesman Jesse Benton and former deputy campaign manager Dimitri Kesari. (Charges against campaign manager John Tate, named in an indictment this summer, were dropped.) Neither denies that the campaign used invoices from a production company to pay Kent Sorenson, the disgraced former state senator who wanted more than $8,000 per month in exchange for bolting the fading campaign of then-congresswoman Michele Bachmann. But attorneys for both men pointed out that paying representatives for endorsements -- illegal in Iowa -- was not a federal crime.

"If you look on TV and see Matthew McConaughey talk about how much he loves driving his Lincoln, he's being paid," said Kasari's attorney Jesse Binnall. "We're less familiar with the idea of politicians being paid being paid, but it happens."

Paul and Kesari sat with separate legal teams at the Southern District of Iowa courthouse, and met disparate but overlapping charges with different arguments. Binnall suggested that his client was victimized by Sorenson, a friend who exploited a non-account, non-attorney who did what he thought was legal.

"You're not going to be able to trust anything that comes out of Kent Sorenson's mouth," said Binnall "His credibility is shot."

Benton's attorney Meena Sinfelt asked the jury to focus on the days that Benton met with FBI investigators, July 21 and 22, 2014. It was difficult for anyone to recall the circumstances of tax day, or another busy financial period. Benton, far from misleading investigators, had been misrepresented by documents and hastily written e-mails.

"What did Benton know on those days?" asked Sinfelt. "What was he asked about?"

The government began its argument with a direct assault on Benton's argument. Calling former Paul campaign controller Fernando Cortez-Mira to the stand, it produced a series of e-mails between Kesari and ICT, Inc., in which he secured invoices in order to pay Sorenson, then told the campaign they were for audio/visual expenses -- and had been approved by Benton.

"Follow the money, ladies and gentlemen," said Pilger, "and you will be able to see the conspiracy in black and white."