Thomas Conway: You might want to take a look at the writings of the renowned British economist and Oxford professor Sir Paul Collier, who has noted that mass immigration provides only marginal economic benefits that largely accrue to the wealthy.  He also notes that mass immigration combined with multiculturalism tend over time to undermine social cohesion, which is the apparent point being made in the opening comment in this string. The cheerleaders for mass immigration and open-ended multiculturalism tend to operate on the basis of broad and cheery assumptions that might not be particularly credible in the real world.