But how has that worked out for you Europeans, socially and politically? Is a USA taking in 600,000-1,500,000 refugees annually a wise idea, a viable long term solution to things? All while propping up the Continent militarily? It is not a solution at all. Particularly when you tout the "need" to get our growth population "under control".
Can you imagine the political backlash? An American version of the anti-immigrant right?
1) As I said, you would be better at integrating refugees and the backlash would be less massive than in ethnically defined nation states.
2) Letting large numbers of refugees become immigrants in Western countries is not a viable long term solution, because it encourages economic migrants to use the refugee system - and props up human trafficking - but we have an acute crisis right now, and it needs to be solved. Long term you need to secure more repatriation (by stabilizing countries and solving conflicts) and invest in better conditions for refugees in countries bordering conflict zones - but the rich countries will always have to take a share and it needs to be better and more rationally distributed.
3) Not sure what the Europe free riding on defence has to do with this - it is two separate issues (and
if you want to link them more refugees in America and more defence spending in Europe would be a sensible trade off).
4) Getting population growth under control is a global problem, and moving people to countries with very resource consuming life styles does add to CO2 emission, but refugees is one group that needs to be taking care of no matter what. Ideally (from my POV) they would crowd out other immigrants, so the net result was the same.