Ultimately it all boils down to that. Once you reach that point you have an unbreachable gap between believers and unbelievers. Sure, they can ally on certain issues and even be friendly. A fundamentalist doesn’t need to have every player on his baseball team be righteous in the eyes of the lord in order to enjoy a nice game on the diamond. That’s true of everyone though, in such a loose knit association morality isn’t so important. Babe Ruth was a cad, Mickey Mantle a drunk, and Barry Bonds shoots up with steroids. Morality is no replacement for the ability to thwack a ball deep into the right field bleachers or a good sinker. This extends to other loose-knit friendships. Religious people have no real issue with associating with well-behaved atheists in business or simple friendly exchanges.
The problems come when deeper associations, such as political or marital ones, need to be formed. Then the two sides run into something of a brick wall. The trouble is that you can’t run an inclusive state, or relationship, believing that the veneration of God trumps all else. It’s a non-starter. You can’t forge a true partnership between two sides when their ultimate intentions are incompatible. The fundamentalist is always going to do what they believe will best serve their faith. That means that while an atheist may vote according to self interest, or who he believes the best candidate is, or even merely according to whim, the fundamentalist is going to have a single motivation, and it’s going to be one that has nothing to do with the sorts of things that should drive voting in a functional society. This might not come into play much of the time, as many religions are neutral on numerous matters of politics, but when it does it does so in a big way.
For example, the political debate on abortion is not so much a debate as a polarized screaming match. The fundamentalists have no interest in hearing reason or logic in matters of public policy, they simply want their beliefs upheld. The same is true in terms of state support of ‘faith based initiatives’ and matters of state religion. If it glorifies God it’s good, regardless of what it does for the quality of debate or those who are unbelievers. I think that the negative impact of religion on this country’s political culture is often understated, by others and myself. It’s what is preventing gay marriage from being recognized, one of the forces behind our disastrous meddling in the Middle East (ever heard of a crusade? Apparently Indiana Jones didn’t engage in the final one.) This country was founded by the descendants of people fleeing religious persecution, but people who were also extraordinarily intolerant towards others, and engaged in persecutions of their own. Even the Quakers, perhaps the most peaceable people on this planet, suffered persecution. Religious people love to talk about how faith contributed to the founding of America, but they don’t mention that it also contributed to all the ugliness of those early days, from persecution of women to slavery. The abolitionists were mostly very religious, but so were the steadfast supporters of oppression. When you put the glory of god above the support of your fellow human beings it is much easier to come up with a dangerous and oppressive government, so long as it claims to adhere to your beliefs. That explains a good deal of why people are worrying about irrelevant little nothings like gay marriage and the pledge of allegiance when there are huge issues of worldwide importance that hinge on this election. The small-minded ignorance and stupidity that religion breed keep them from seeing the big picture.
I don’t really want to talk about the interpersonal side of things, because it’s less important. Suffice it to say that I don’t think religious people and non-religious people should intermarry, unless the religious person is a hypocrite. There are problems with child rearing, values, and expectations. One of the typical stereotypes about men from a bygone era was that they would stay home and watch football while the wife would take the children off to church, their father undermining their religion by setting such a bad example. What a crock of shit. Showing that religion is voluntary, that not everyone is a believer, and that there are better things to do on Sunday than to go listen to lies is a gift. See that’s the way us heathens think, and that’s a major problem. It’s not like when one person thinks the most important thing is honesty and the other thinks the most important thing is preserving peace. That’s something that can be worked on. When one person believes that the greatest thing someone can do is show love for Jesus or Mohammed and the other thinks that the two guys were just incredibly successful snake oil peddlers, how do you resolve that? You don’t.
Unbelievers look on the faithful as a curious brand of psychotics. They are involved in a mass fantasy about how the world works and aren’t interested in empirical evidence. When asked how they can believe anything that ridiculous they say, “Hey look, I’ve got a pretty old book here, and it says stuff. There’s also this guy who stands at an altar and when he’s not touching little boys tells me that the book is accurate, so long as you ignore certain sections and interpret others in a special way.” When we point out that there are other, better, books out there that contradict their book and empirical scientific evidence of its falsehood they get angry or look at us in a puzzled way and say “No, you see, my book’s right. That’s the difference.” Point out that there are literally hundreds of religions that all think they’re right and that not all of them can be, and they don’t care. Talk about evolution, genetics, the psychosocial explanations for their beliefs, and they shrug it off. It’s like trying to tell a schizophrenic that the CIA isn’t actually out to get them. They might hear you, but without heavy medication they aren’t going to listen.
That’s what it comes down to, trying to reason with the clinically insane. There are some people who have relatively harmless delusions, and those are the casual churchgoers. The ones who might go every Sunday or might not, give plenty of lip service to their faith, but put secular morality above the divine. There are lots of them, and they are not a problem for secularists to deal with. If you place "Thou shalt not kill" far above "thou shalt not take the lord’s name in vain" then there is no beef. That’s when it’s a harmless foible. But those who put their faith first, how can you reason with them, how can you compromise and create a society that works for everybody? Be it suicide bombers in Israel or Pentecostals in Arkansas, I don’t have an answer. For now the politicians have all decided to bow and try to play the game, especially on the Republican side, but that has dire consequences.
Religious fundementalists are willing to kill and let others die for what they believe in, even if the other people don't. They've burned unbelievers at the stake, taken away their voting rights, and refused them employment at federally funded social services. They'll kill abortion doctors and blow up busses for the sake of what they believe in, and cheer on such acts as moral, normal, and sane. How can you build a society with people like that? People who respect a myth more than a human life. People so caught up in their own delusion that they'll orphan children for a symbolic victory in their cause, and if they won't do that personally then at the least they will support such heinous acts.
You can’t be a good citizen if you put god before country.