Is Matt Bevin responsible for his recent rise in popularity? No, he is most certainly not. One of the most difficult tasks for a campaign in which the candidate is not very well known is elevating that candidate's name ID. We can go back to the case of Rand Paul in 2009-10. Sure, everyone knew Rand Paul's daddy Ron Paul but he certainly didn't have the name ID of his father in Kentucky.
A combination of outrage towards McConnell from Tea Party activists, and Fox News, elevated Rand Paul's name ID. The nasty business of forcefully retiring the old ball player Jim Bunning and ordaining his successor in Trey Grayson backfired on McConnell and when the poll numbers shifted McConnell sold Grayson down the Ohio River. He made a mistake by misjudging the power of the Tea Party movement, at that time. Now he is making another mistake by treating Bevin as a legitimate threat. At this point Bevin is not a threat. Let the news cycles run with it but don't provide the fodder for the media.
Now McConnell has never been shy about attacking his opponents, he will spend the cash to bash your head in but I think he is going a tad overboard in his early attacks on Matt Bevin. McConnell's campaign team is handing Matt Bevin the golden egg, they are elevating his name ID for him. Matt Bevin is saving huge amounts of cash and McConnell himself will be indirectly responsible for raising more cash for Bevin. Sure it appears Bevin is spending a lot of money "responding" to McConnell and that negative ad arms race might come back to haunt Bevin in the end if he fails to properly manage his campaign cash.
We should have a new round of poll numbers this month, or early next month, that will most certainly show a rise in Bevin's name ID. In a few months we will have enough data to conclusively prove that. In a June 2013 Wenzel Strategies Poll Matt Bevin had a 14.6% approval to 21.1 non approval, or unfavorable rating, with a whopping 64.3% with no opinion of Matt Bevin. That means roughly 65% of the GOP Primary electorate have NO idea who the man is. I suspect a 40% no opinion in September and if McConnell stays the course in attacking Bevin he will have a 25% no opinion by Christmas with Mcconnell being responsible for at least 65% of Bevin's rise in name ID. McConnell led Bevin 58.9% to 19.9% with 21.2% undecided in that same poll. Why commit millions in attacking, if he's spending that much, Bevin while you lead him by roughly 40 percentage points? It makes no sense.