Is interfaith marriage becoming a danger to organized religion?

You bet it is and I’m glad to hear the good news because organized religion deserves all the speed bumps it has to cross.
In the U.S. interfaith marriage has increased from 20% to 45% in the last 50 years. These marriages are made up of people seeking common ground and to them values matter more than beliefs. This is threatening to religions because it greatly reduces the chance of their children being indoctrinated in a faith.
It is important that people be weaned away from religions and ,most importantly, their allegiance to holy books. It is the later that leads to dogmatism and intolerance and there is no doubt the world can do with a reduction in both. In general, people not indoctrinated in one faith can figure out their values and morals on their own and that is a good thing.

I participated in the survey for Dale McGowan’s latest book on that very subject. In Faith and In Doubt. He starts out discussing the old myth that interfaith marriage is bad. It never has been, at least not for the married people. It is no doubt bad for the religious leaders for the reasons you mentioned. In the chapter on raising children he concludes the best thing for everyone is to let the kids decide for themselves. I’m hoping that is the trend for the whole world.
He also talks about dogmatism in general. It is not only a problem for an atheist marrying a dogmatic believer. A believer marrying a dogmatic atheist is just as likely to end up in divorce.
It’s a great book, not just for people in mixed secular/religious marriages, but to get a different perspective on belief in America. His survey did not simply ask believe/not believe, he went into details about what you believe and to what degree. He found there is very little correlation between what people actually believe and what their denominations say they should believe.

I think increasing interfaith marriage is a symptom of the decline in people valuing the faith they were born into. It’s part of the larger trend away from religion in general, and a repulsion of keeping religions separate and the old dogma of “us and them”. People don’t believe the old tales about what those (fill in the blank)s are like anymore.

I think increasing interfaith marriage is a symptom of the decline in people valuing the faith they were born into. It's part of the larger trend away from religion in general, and a repulsion of keeping religions separate and the old dogma of "us and them". People don't believe the old tales about what those (fill in the blank)s are like anymore.
That's been happening within Christianity for a long time. C.S. Lewis covered it in his introduction to Mere Christianity. It also appears to have been a strategy of the religious right to bring more people in under the banner "Christianity". It is now easier to say "all Christians do X". I think this has led to prejudice against all Muslims, despite the spectrum within their ranks as well.

Yes, I definitely believe so for the reasons already mentioned. On a slightly unrelated note, I was just thinking a few days ago about how when I was a teen, about 10 years ago, how most churches are desperately trying to create a viable “teen” or young adult program as if they are able to somehow make it interesting or appealing enough to young people, they will flood the church again–I was pondering it and my belief is that due to the endless facts, ideas, concepts and diverse views available at our fingertips nowadays, it’s no longer a matter of the programs not being interesting enough, it’s a matter of absolute disinterest due to non-belief. Essentially, churches can make it as interesting and appealing to young people as they want, but it’s not going to sway beliefs.

Yes, I definitely believe so for the reasons already mentioned. On a slightly unrelated note, I was just thinking a few days ago about how when I was a teen, about 10 years ago, how most churches are desperately trying to create a viable "teen" or young adult program as if they are able to somehow make it interesting or appealing enough to young people, they will flood the church again--I was pondering it and my belief is that due to the endless facts, ideas, concepts and diverse views available at our fingertips nowadays, it's no longer a matter of the programs not being interesting enough, it's a matter of absolute disinterest due to non-belief. Essentially, churches can make it as interesting and appealing to young people as they want, but it's not going to sway beliefs.
You're right. They can lead a horse to water but they can't make it drink. A good thing in this instance. Lois

No, it isn’t for two reasons:

  1. The mixed beliefs will create new religions (or at least denominations).
  2. Most modern marriages won’t last.
No, it isn't for two reasons: 1) The mixed beliefs will create new religions (or at least denominations). 2) Most modern marriages won't last.
There is some anecdotal evidence for #1. But nothing for #2. And the McGowan-Sikes data I mentioned earlier says the opposite. I don't know if this is published anywhere other than in his book. As to #1, religion has been undergoing a major transformation for 100 years now. A backlash like "fundamentalism" is an indicator of that. And I don't believe returning to the old ways is winning. It has reached pretty high into the Republican Party, but it is harming that party too. I don't think it will successfully get control of any army large enough to sustain itself, not more than a decade here or there anyway. That leaves watered down versions of spirituality. Those are a threat but not on a large scale. Don't get me wrong, all of this requires maintenance of our worldwide scientific community. I hope we squash all the major religions before that infrastructure collapses or the whole cycle will just start up again.

Reminds me of the line: “We were divorced because of religious differences; he believed he was god and I didn’t.”
Lois