Humans are pulled in two directions by the “nurture” part of “nature/nurture”: in the direction of the moral code ingrained in you by the people who raised you, and in the direction of the moral flexibility needed to coexist with others in a larger society. Disagreement on core issues is a dealbreaker if your upbringing led you to value a moral code more than the need to coexist in an increasingly liberal society led you to value the need to seek a morally relative perspective. Hypocrisy is a dealbreaker if your training in and valuation of moral relativism has a greater hold on you than your training in the need to value some specific moral code.
As Neal Stephenson points out in a retrospective of hypocrisy in the early twentieth century, “in [a morally relativistic] sort of a climate, you are not allowed to criticise others – after all, if there is no absolute right and wrong, then what grounds is there for criticism? [But] people are naturally censorious and love nothing better than to criticise others’ shortcomings…Hypocrisy [was] elevated…from an ubiquitous peccadillo into the monarch of all vices. For, you see, even if there is no right and wrong, you can find grounds to criticise another person by contrasting what he has espoused with what he has actually done. In this case, you are not making any judgment whatsoever as to the correctness of his views or the morality of his behaviour – you are merely pointing out that he has said one thing and done another… Many of the persons who [despise hypocrites] were, of course, guilty of the most nefarious conduct themselves, and yet saw no paradox in holding such views because they were not hypocrites themselves – they took no moral stances and lived by none. So they were morally superior to [the hypocrites] – even though – in fact, because – they had no morals at all. Most of the time [hypocrisy is] a spirit-is-willing, flesh-is-weak sort of thing. That we occasionally violate our stated moral code does not imply that we are insincere in espousing that code” (The Diamond Age, 190 – 191).
The point being that people still vote for politicians they believe to be, in their private lives, morally bankrupt hypocrites is because they value some or another moral code more than they value their disdain for hypocrisy. And also that violating a moral code is a merely human thing to do, and that it does not translate to universal insincerity of character.
As for me – well, I can’t really relate to the example you give in your question, because I have no interest in voting for Republicans. But I do have this friend I was very close with in college, who later lied to me in the worst way I can imagine, and has now successfully taken his first step towards his longtime goal of becoming a force in American politics. I asked myself, would I ever vote for this man, even though I know beyond the shadow of a doubt that he is a liar and a cruel person? Doesn’t this mean he would just say anything to get ahead? But…I think my answer is yes, because I believe that even if he is a liar, he still believes strongly in pretty much the same political agenda I believe in. And this agenda is way more important to me than his personal shortcomings, and more real to me than doubts I have about his character. So yes – while hypocrisy bothers me a little, I would still vote for a candidate I knew to be a hypocrite.
@Qingu So – no, evangelical Christians do not, generally, care about hypocrisy as much as they care about the issues. Added bonus that their particular moral code leads them to see hypocrisy, and human vice in general, in a similar light to Stephenson’s.