Sullivan may vacate the 18 USC 1001 charge, and then charge Flynn with perjury.
You can't lie under oath to a federal judge.
1. A Federal Judge can NOT 'charge' anyone with a crime.
According to legal precedence Sullivan has no option but to dropt the case; however, he is bringing in his Trump-hating pal to discuss the ability to 'find' Flynn in COMTEMP of court.
2. Democrats lie under oath all the time. If all of their Democrats who lied under oath were in jail today, Gitmo would be full.
The last President to lie under oath and be found in Contempt was Slick Willy. He was given no jail time, but he did his license to practice law temporarily stripped.