In this case, pushing the country to a more aggressive war. Currently it is only being fought with words and the courts, and what government each controls.
If they do go with the voter fraud on the level you are talking about, it will get ugly. They are all about the long game, but they seem to be unhinged by Trump and may get blatant about their fraud. If that happens, it may push some to violent resist. At that point it gets truly ugly.
The Leftist might think they can just take control but there is a limit to what people will take. They may well go over that limit. I am not sure what happens then, but I doubt it will be a pretty process.