I still don't understand why this will make Republican voters stay home.
What do Rev. Haggard's sins have to do with keeping taxes low, protecting the American people from terrorists etc.?
Nothing, but why did the "values voters" go to the polls in 2004? Mostly because of the protection of marriage, abortion, and other morality-based issues. At least that's what Karl Rove seemed to believe based on the campaign he ran. Haggard has been at the forefront of these issues which is why his fall from grace is a big deal.
In any case, the biggest problem Haggard has now is that he is still reluctant to come clean on what he did. First he did nothing wrong, next he committed an indescretion, now he paid for a massage from a gay hooker but didn't have sexual relations, and bought hard drugs once but didn't use them...
Does that remind you of anyone?
In the long run Haggard's evasions and lies will be more damaging to him than any drug use or sexual "indescretions". It shows that he is still in denial and cannot be trusted to tell the truth. Such a man should not be allowed anywhere near a pulpit.