We have many regulations, justified in many ways. One common type of regulation prevents people from making and enforcing certain voluntary agreements, and one common justification for such regulation is that we protect people from hurting themselves via such agreements. For example:
We either have a plurality of sovereign nations each with their own set of laws (which in principle) suit the cultural needs of those within their borders.
The alternative is either global government or attempting to enforce your laws overseas which gets tricky kind of fast.
You can just travel to Nevada for prostitutes.
Status considerations may be important in many cases, but you guys are obsessing about them :-)
Isn't the refusal of alternative 1 simply a problem of avoiding "cures that are worse than the disease"?
There can be many credible and legitimate reasons why someone wants to migrate from country X to country Y (for all X and for most Y).
"We" may not want to cause harm by preventing such legitimate migration just because it would open a loophole for someone who would be migrating just to do something-we-don't-like-even-if-they-do-it-far-away-from-us (probably a small fraction of those who would like to do something-we-don't-like-even-if-they-do-it-far-away-from-us anyway).
As to alternative 2, it seems unrealistically complicated and costly to implement - and not only because, as said in some comments already, it would be very hard to prove that someone would leave the country unless it is exempted from some laws.
Anyway, I'd guess that if the State got sufficient information that a family would migrate to do "something bad" to a "vulnerable member" of that family, then that "vulnerable member" would be put in the care of social services and the other members would be given restraint orders (to be clear: I am saying that it would be politically feasible to commit to do otherwise). And if no family member could be identified as "vulnerable", then "we" would say that "they" are not part of "us" and they may just as well get out of "our" country.
Earlier discussion of tainted funding of anthropology and health-science.
I don't think you can dismiss the us/them theory so quickly just by pointing out that we allow people to go to Thailand to see whores. The set of people who are willing to go through the trouble and expense of traveling overseas in order to do something is a small fraction of the people who would engage in it if it were legal at home.
Additionally, that fraction which travels abroad is going to be the wealthiest subset of the lot; it's more difficult AND we're less interested in regulating the behavior of the rich.
We all have a taste for altruistic punishment.
I would certainly vote for not allowing drug sales, prostitution etc. in my neighborhood, and for using my local taxes to enforce those rules. I would be more enthusiastic about using my taxes for that purpose than for more public health care or public schools. Bars don't bother me so much, but the majority of my neighbors on Central Park West evidently feel differently, which is why the zoning prohibits such activities. I don't know as polygamy affects the neighborhood, but I would certainly oppose allowing polyamorous individuals to live in our building, as we wouldn't want our children exposed to that sort of thing. So for me, spending my tax dollars to enforce my morality in my immediate neighborhood would definitely be utility-enhancing, especially compared to the sort of nonsense that the City Council is usually trying to spend my taxes on.
What would happen if taxpayers were allowed to directly allocate their taxes? In other words...what would happen if people were forced to put their money where their mouths are?
It's one thing to vote for marijuana to be illegal but it's another thing to spend your own money on enforcing the rule. It's one thing to vote for polygamy to be illegal but it's another thing to spend your own money on enforcing the rule. It's one thing to vote for prostitution to be illegal but it's another thing to spend your own money on enforcing the rule.
The key concept here is "opportunity cost". You can't have your cake and eat it too. How much national defense, public education, public healthcare, infrastructure, etc would people be willing to forgo in order to ensure that laws against victimless crimes are properly enforced?
You can be a utilitarian who rejects groupism completely and reject paternalistic interventionism and coercive migration barriers if he sees more harm then good in them.
Emigrating may not be illegal, but it is very inconvenient.
Still a strong signal to pay significantly more taxes just to enjoy polygamy (which, unless you are hell bent on enshrining it in contracts before the law, you are allowed to do anyhow in most Western countries)
And the law gets really wierd in some cases especially with sex tourism.
It's illegal for an American to travel abroad to have sex with a person under the age of eighteen. Where it gets really tricky is lets say you travel abroad for other reasons and then end up having sex with a seventeen year old (technical legal but hard to prove) or (more common) it's not illegal to have sex with a seventeen year old in the country you are visiting (or even the US state you are a resident of).
These laws have always bothered me. I'm pretty much against making it illegal to break your laws in a different nation and prosecuting them on return. Imagine if Germany passed a law stating that it was illegal for French citizens to exceed Germany speed limits while in America and then prosecuting French tourists when they crossed the border to get good beer.
Well, it's true that there are few Americans who would wish to prevent their compatriots from traveling to Thailand to use cheaper prostitutes, but my observation still applies - "Out of sight, out of mind". What happens in Thailand, stays in Thailand, the purity of sacred homeland (the territory claimed by the ingroup) is preserved and the johns skulk back without much notice. Homo hypocritus is mainly interested in maintaining appearances close to home.
I must say, I know of one exception to this indifferent attitude - a former secretary of the WTA, who earnestly insisted in a mailing list exchange that UN troops should be sent to Thailand to prevent American males from frequenting local houses of ill repute. A rather unexpected demand from a self-proclaimed polyamorist yet perhaps less surprising in view of his advocacy of dolphin and ape rights which may indicate he has an unusually broad ingroup, at least when thinking in the far mode. But I guess I have digressed enough already.
This. Stephen Diamond has hit the nail exactly on the description of your questions, and his general answer is partially correct.
But here's another piece: In general, laws are passed in response to problems. You could argue that there simply isn't time to deal with all the problems that we have, or that we only care about the things that cause politicians to get campaign funding, or any of a number of other complaints about the political process, but ultimately, the things that get passed tend to have at least a passing relationship to things that have recently happened.
We've never had a trend of people moving to other countries to practice things that are illegal here. It's not terribly surprising that we haven't, since it's so difficult to move to another country, and there are few countries that are enjoyable to live in and allow exactly the thing that our country does not. But even if it does surprise you, that trend has never happened here in the United States.
But it has happened elsewhere. Communist countries consistently had problems of people moving to the West because of freedoms they denied, and so, for the protection of the people, they banned emigration. Exactly as you say no one does.
I'm glad it was overturned. I see no philosophical reason why a nation should have the right to force citizens to stay. I'm amazed how humans can be treated like cattle and people tend to accept it because "it's the law".
Ireland tried to close the leaving-the-country loophole in the 1992 "X Case."
The case of a 14-year-old Irish rape victim barred from traveling to England to obtain an abortion has provoked a debate over how far judges and officials in Ireland can go in enforcing the nation's explicit prohibition against abortion.Today, an Irish High Court judge in Dublin affirmed an earlier court order and issued a permanent injunction forbidding the young woman to obtain an abortion in England, where the procedure is legal. Members of the Irish Parliament who are sympathetic to the girl's plight say they expect her family to appeal the case to the Supreme Court.
The injunction was later overturned by the (Irish) Supreme Court.