Hi Bill,
From what I understand, it seems as though the fundamental basis behind your argument against changes in marital liberty is that it could provoke
further changes - the "slippery slope".
What distinguishes this situation as being a "slippery slope" from being "progress"?
It seems to me that where we disagree though, is the existence of a causal relationship between polygamy and each of the outcomes that you have described, or at least, the severity of each one.
1. Men will decide to use water torture rituals to raise their children because they have more than one wife? I question this as being simply absurd - cannot identify any causal relationship! Whoever would do this clearly has other problems, and their polygamy is certainly not the issue that needs addressing.
2. Neglected children - I agree that this will be causally increased in SOME cases. But this is the fault of the person's character and morality, not their polygamy, and I suspect that anybody prepared to neglect their children due to polygamy is probably already doing so, monogamously. Polygamy is not the issue that needs addressing here, but the person.
3. Increased competition against young males - possibly. But I doubt this would be extremely severe in effect. But this should force young males to increase their merit for attraction (skills, career, etc.) - anybody who is only able to attract a lady because all the other blokes are unavailable (as a result of monogamy) is a pretty sorry state, and should be encouraged to improve somehow.
4. Multiple underaged wives of older men: do you mean legally, as in, paedophilia? What the heck is the link there? If you mean underaged as in, comparatively young, then of course that's their choice to make.
It seems as though the argument is also fundamentally based upon the fallacy "argument ad antiquitam" - appeal to tradition/old ways, i.e. 'x is better because it's been like that for many years'. If this argument made any sense, we wouldn't get anything done.
An interesting topic to consider, nonetheless. To be honest, I don't even feel strongly about same-sex marriage/polygamy in particular, as I don't feel it affects me directly. However, I do care about our rights and liberties as people, which encompasses this issue. And as far as rights and liberties are concerned, despite them not directly applying to my life, I recognise the following:
Injustice anywhere is a threat to justice everywhere.
- Martin Luther King Jr., Letter from Birmingham Jail, April 16, 1963