So he says here.
I have to admit I'm a bit puzzled by the reaction of many to the prospect that Sherrod Brown is in too. Sure there may be an issue with whether or not Brown gave Hackett the "all clear" signal and then changed his mind and perhaps (though I don't put too much stock in the importance of this in this race) some influence by the DC people (denied).
But, generally, I think primaries are a good thing assuming the candidates don't nuke each other (and they shouldn't). In this case we have an establishment candidate, Brown, who has one set of advantages, and we have Hackett who has another set. Let them take it to the primary voters in Ohio. It can only serve to enhance awareness of the race and increase the name reocognition of both candidates.
Let them have a healthy campaign and a healthy debate. As I said - as long as they don't nuke each other a primary is a good thing.