Pat Roberts from Kansas looks like he might be replaced by an independent, if the Democrat is allowed to withdraw his name from the ballot, which he is still attempting to do.
Roberts has no connection whatsoever with Kansas. He lives in Virginia and basically only lived here for a short time prior to his initial election. It's sort of bizarre that he lasted this long, actually. The problem is that he only gets challenged by nutcases like Wolfe in the primaries (too nutty even for Kansas), and Kansas is too damn red to vote for a blue senator. Technically, I'm not even sure Roberts should be eligible, but that won't stop this state from declaring that he is even if he's technically not by most measures. His Kansas "address" is a front, not an actual residence. The trouble with this state is that one political party overpowers the other so much that they can be pretty much as corrupt as they want to be. That isn't to say all of them are all of the time, mind you.
The other senator from Kansas is completely secure, and not nearly as bad as some... way to conservative for my taste, but neither a complete idiot nor a scammer.