Sorry but the time for that threat was after the 2016 election and the 2018 election when Trump was claiming vote fraud. And the chance to turn that threat into action is long since past. Trump could have made vote fraud prosecutions a priority for his Justice Department. He didn't, and he paid the price.
> Other people involved in this fraud will be prosecuted to the fullest extent of the law.
This line was not really intended to be true.
It was just meant as a little push, to help convince the lower level participants in the fraud to try to confess early and get rich rather than risk jail. The higher-level leaders would expect that their connections would protect them anyway.