I have a hypothesis:
The reappearance of birtherism in Arizona is DIRECTLY related to the fact that the republican's here feel vulnerable in the upcoming election.
Hear me out...
The secretary of state has proven himself a fringe (or at least highly influencable) whacko by running down the birther rat-hole. He "backed off" yesterday, mostly because he discovered the hard way that the loud lunatic fringe is drastically outnumbered by the silent majority, and the latter are the ones who will keep him out of the governor's mansion. He can kiss what political capital he had with independents and non-fringe republicans goodbye.
Sheriff Joe, not to be outdone, is now spending MY MONEY AS A MARICOPA COUNTY TAXPAYER to send a deputy on a junket to Hawaii (nice job if you can get it) because he thinks the long-form birth certificate previously released by the president is a fake. (Just out of curiosity, under what statute does he think this is part of his jurisdiction? Aren't there some brown people in the county that are in need of more harassment? At least then he's only being a LOCAL racist.)
These are two highly placed state republican's with national levels of attention on them. And rather than doing their jobs responsibly and sanely, they are both off chasing down a conspiracy theory that has been debunked over and over again, quite thoroughly, including by Bill O'Reilly.
Why? Fear. They are afraid that Obama just MIGHT challenge Romney in Arizona. They fear that, given another term, Obama might just push through some of those "crazy" ideas he has, particularly around all those brown people, which would eat into some of their white privilege. This is the same urge that resulted in Clinton's impeachment; if we can't beat them on the issues, let's go after something unrelated.
The republican's are running scared, and this "rebirth" of the birther controversy is just more proof of that fact. Our job now is to keep them on the run.