Trey Grayson has said he won't challenge Jim Bunning. But nothing is permanent in politics so it's interesting to delve into the numbers to see how Republican voters in Kentucky feel about the two.
The largest group of GOP voters has a positive opinion of both of them, at 29%. The next biggest group has a favorable opinion of Grayson and disapproves of Bunning's job performance. They make up 18% of Republicans in the state. 15% have not mind their minds up about either of the men. 12% dislike Bunning but have no opinion of Grayson yet. 10% like Bunning and have no opinion of Grayson yet. 6% like Grayson and are ambivalent toward Bunning, and the same percentage say they dislike both officials. Only 3% say they approve of how Bunning's doing and have an unfavorable opinion of Grayson. That's not much of a base to start from in a contested primary. There is basically no one who has not formed an opinion about Bunning and has a negative view of Grayson.
Combine the folks who like Grayson but not Bunning, the folks who like Grayson and have no opinion about Bunning, and the folks who don't know enough about Grayson to have an opinion but have a poor opinion of Bunning and you're at 36%. Combine the folks who like Bunning but not Grayson and the ones who like Bunning and haven't formed an opinion about Grayson and you're at 13%.
That would leave half the electorate either liking both men, holding no opinion about both, or disliking both and Grayson needing to pull only about 30% of those remaining voters to get to 50%+1.
Grayson likely won't challenge Bunning. But he'd probably win if he did.