This could easily go much longer and following this lead is going to entail a lot more research, but immigration is in the news a lot and so I looked into it some. 
     Having traveled around the world, I can give a firsthand report on what it was like in many other countries, and I will say right off that most of them weren't very diverse. It would have been tough for me to make a go of it in a country where I didn't speak the language and knew no one so I know what immigrants are facing, to a degree. Best case scenario is they might be either highly educated or hooking up with family or friends, which would make their resettlement much easier. 
      I also know that many of the developed nations in the world are facing an either flat birth rate or a declining birth rate. Futurists point that out to leadership of those countries and bring the point home to them that in X number of years we are going to be losing key demographics here and that can be translated as comparatively saying "Hey, Joe Congressman! We're going to lose our base!" which means that power will be lost. So, it's understandable, facing this threat, that the present day powerful would align themselves strongly with the conservative religious, who decry gay people and abortion, which are two depletions of the base, right? Not a lot of population growth there. Also, they would be upset that dilution, in the form of immigrants, would be changing the balance of power, and that those immigrants would most likely be settling into the neighborhoods where their base tends to live. Oh it all makes sense. 

     I looked into other countries to see if anybody was moving there. Canada is taking in a lot of people from everywhere, as is a lot of Western Europe, but....  ...not very many other countries around the globe are open for resettlement. China, India- they don't want immmigrants because their populations are burgeoning. In war torn countries obviously not, backwater countries with small economies, not much. And that's a lot of the rest of the world! Countries that have economies that are strong, like Japan (I can't think of anywhere else right now)- well, I've been to Japan and I seriously stuck out, let me put it to you that way. 
     Japan and Italy, interestingly enough, have the greatest discrepancy between birth rates and death rates, both populations are projected to decline, yet I don't think- correct this with your own research if I am wrong- that Japan takes in a lot of people. Italy has been innundated with refugees because it's right there on the Mediterranean Sea, sticking out like a giant boat ramp, which is putting pressure on the government, big time. Japan, not so easy to reach. 
     Russia is not a destination resort, nor is South Africa, which has corruption problems. Norway, surprisingly, seems to have the welcome mat out, according to the immigration map I viewed, but....do you really want to live there? It's cold. A lot Australia isn't exactly friendly towards anybody coming in looking to make a home there and nowhere on the globe can the wagon train set out to bring pioneers to the promised land anymore so what is any government to do? Take 'em in, take only a few in and call it a day, close the door altogether, or deport the ones inside already but that's a legal and moral mess and welcome to the world, circa 2018. Can't send 'em back to the blasé or horrific conditions from where they came, the governments there don't want them anyway, and at home you can't please the base, there are not enough jobs, housing is in short supply please government DO something but government says you're costing us too much already (but we have the 1% and star athletes making bank and CEO's making thirty times what the average Joe makes in a year). Geez . How did it get this way? 
     I don't have the answers to any of this and if I did I couldn't implement them much so leaders, lead! That's what you volunteered to do. We'll vote yea or nay when the report card comes out.