I didn't realize AZ had open primaries. The blame I think falls into the lap of the RNC; look at how open primary states affected the outcome of the last GOP nominee ... nothing more needs to be said.
In AZ, the Primary (open) is a different election than the Presidential Preference election (closed). The Primary that's open is always 60 days ahead of the General Election in AZ, which is why McCain-Feingold tried to rig the funding dates the way they did. Under M-F, no PAC could have run commercials against McCain for the entire three months prior to the General Election.
The dates for the funding cutoffs were tailor made for just one Senator, named John McCain. All the other states have different dates, but only AZ had the dates set up like this.
Fortunately that was the part of the law SCOTUS kicked out.