Fortenberry is accusing the prosecutor of being biased because he has donated to Democrats, but the prosecutor has also donated to republicans.
He is trying to portray that he was confused rather than a liar over the source of the donations, so he wants to bring in an expert witness, a professor whose area is aging and memory.
I've followed this from the day he the FBI announced he was under investigation. He and his wife sat in their car for an interview and tried to tell reporters they had no idea why he was being investigated by the FBI.
The OWH carried a story on it today, also. I found this remark by the prosecutors amusing:
Prosecutors called that argument absurd. They noted that Chagoury gave to both Republicans and Democrats and said Fortenberry is not a prominent politician in (California) or otherwise widely known outside of his district.
So basically, who do you think you are, Fortenberry?
OWH article:
https://omaha.com/news/state-and-regional/govt-and-politics/fortenberry-wants-jury-to-hear-from-expert-on-memory-and-aging/article_64b0e862-8603-11ec-81d9-37911ae4e7a4.html