After winning the American revolution, our founding fathers decided against establishing any kind of monarchy. Leaders who hold power for an extended length of time become corrupt and/or lazy without having said power checked from time to time.
There is a preference for incumbents in our system today because the conventional wisdom leads one to believe that since said candidate has won election before, he should do so again. If your goal is nothing more than winning elections, there is some logic that applies here. But, if your goal is to advance an agenda then it is vital that you have a candidate that wants to advance that agenda. Let's face facts: the whole point behind politics is to advance an agenda.
If your agenda is nothing more than winning elections, then blind support of incumbents is the way to go. Feel free to go ahead and schedule the coronation of your monarch, but don't pretend that you are in it for an ideological agenda.
I'm not suggesting that one shouldn't support an incumbent, I am saying that you shouldn't do so simply because the candidate is an incumbent.
I really like "sparring" with Matt from Lincoln Logs because he's a smart guy. When he's got a candidate that he cares about, he supports that candidate with a good case. But, Matt is also a "big tent" Ohio Republican when it comes to other races. Take the DeWine primary, for instance. Whenever the race comes up, Matt goes to the old standby, "DeWine is the incumbent." It doesn't seem to matter to Matt that DeWine isn't advancing the conservative agenda. All that matters is that he's won before.
Democrats used to think like that too.
It isn't enough to just win elections, we MUST do something with the victories. That is what advancing an agenda is all about. Maintaining the status quo isn't enough...at least, it wasn't for our founding fathers.
The Ohio GOP? I'm not so sure...