Fair enough to disagree... I'm just confused that someone would ask for a citation, since it's clearly just a projection or opinion.  Maybe he just wanted me to defend it, rather than just claim it...<p>That said, do you really think that "unrestricted" immigration (excluding border cases of known criminals, etc...) in the US (or Canada, Australia, etc) would not have a substantial negative impact on quality of life?  It seems obvious to me that it would, but if you have any good arguments, studies, links to the contrary, feel free to post - I will read them.