That the advancement of civilization can be thrown into reverse via mass immigration, is admitted, in a roundabout way, in the below quote, where the effect of such restrictionism is noted to be one of "inducing labor-saving innovations": " The primary policy pursued by every rich country is to prevent unskilled labor from moving into their countries. And because unskilled labor is the primary asset of the poor world, it is hard to even imagine a policy more directly inimical to a poverty reduction agenda or to “pro-poor growth” than one limiting the demand for unskilled labor (and inducing labor-saving innovations)." quoted from Lant Pritchett via Econlog:http://econlog.econlib.org/archives/2007/05/lets_increase_p.htmlThere is a grave difficulty for power-greedy elites in speaking rationally
on the subject of the desirability of mass immigration of undesirables.
If they were to do so, they would forfeit the chance to try to smear and 'diagnose'
all opponents of their openness-valuing position. Ref.:Parapundit 6-24