The absolute number is all that matters. A person immigrating to a country with a low population has a disproportionate affect on that population compared to a country with a large population.
Also you're implying that immigration is good and desirable. That's certainly up for debate.
I didn't intend to imply that immigration is good or desirable; it just is. It's a fact of life. I merely wanted to point out that the ratio of immigrants to natives in the US isn't particularly unusual.
(I'd say it's obvious immigration has huge potential but also considerable risks to the host country). In the long run, I suspect immigration is almost always a positive.
My guess that immigration is positive in the long run (I mean over timespans greater than a human life) isn't something to take seriously, I certainly don't ;-).
But the argument goes as follows:
- Long term immigration tends to happen where the it's supportable. People don't usually go somewhere they're likely to starve. (So there's generally going to be some feedback loop that prevents really crazy immigration excesses - at least usually, I'd guess).
- Countries/regions/whatever with greater population tend to in the long run have more influence and greater development that those with less.
- Diversity is a strength to a society (but not necessarily it's citizens!) for various reasons, but e.g. creativity and resilience in the face of a changing world are likely higher simply because you've got a better shot of finding the right person(s) at the right time for the right task. This is a bit speculative; but there are parallels in evolutionary biology and business, so it appears plausible to me.
- Choosing to migrate is a non-trivial affair. Migrants tend to therefore be more enterprising. At the very least, the ability to successfully migrate, stay, and raise the next generation is a kind of test of capacity. This is the converse of a brain-drain if you will. Having said that, just because somebody is "smart" doesn't mean they'll achieve much in their new life; after all, needing to adapt just isn't that easy, and the deck is stacked against them. But over generations at least you'd hope for sufficient integration to overcome that.
To be explicit: This is mere speculation; and even as far as that it only suggests general patterns. Not all migration might be positive; and it might take a long time for the benefits to materialize, and even if society is better off doesn't mean that those that lived through the integration process are better off; and even then it doesn't mean the old population is better off either (though you'd hope so). And of course it's all a little hypothetical since you won't be able to stop migration no matter what, so the interesting question is whether the way you manage it (or not) matters, and what those choices might be.
You brought up the interesting question of whether immigration is good (at least, I hadn't considered it quite like that before), so this is just my best guess.
Thanks for your polite, well-thought reply. I used to be more pro-immigration/open borders but have since swung the other way. I'm glad that you (as I was) are open to new ideas. The mantra right now is immigration == good. Whenever something is taken to be true, such as that, I question the prevailing wisdom and ask, what if this weren't true? Or better yet, who is this good for? How does this help me in particular, or people in a similar situation? Etc....
Also you're implying that immigration is good and desirable. That's certainly up for debate.