Well, he didn’t win. He won by a few votes, and it was later discovered that many votes were from felony convicts. If those votes were removed he would have lost, or they would have ginned up another box of votes out of the trunk of a car.
He should have been tossed from office when the voter fraud was revealed. I’ll never understand why he wasn’t.
There should be mandatory jail time for candidates who win by fraud.
The thing about that is unless they are incumbents (or holders of other powerful offices like then WA State AG Christine Gregoire who stole the 2004 Governor's race) it's unlikely they were involved in the fraud themselves, rather others do it on their behalf. I doubt one could prove Franken himself committed a crime.