The Right-Wing Version of Eric Pianka
On Brookes News, they're explaining the good side of bubonic plague:
Was the decline in living standards due to the population rise or was it due to the earlier population drop?
After the Black Death struck England in 1348 the population was reduced by about a third. The result was a rapid rise in real wage rates. So swift was this rise that in 1351 the crown felt impelled to pass maximum wage laws based on the average wage for the period 1325-1331. It did this in the belief that there was something unnatural and unjust about rapidly rising wages, even though it was brought about by a sudden reduction in the size of the workforce.
Any economist would simply state that the sudden rise in real wages was caused by a rapid increase in the ratio of land and capital to labour. (This process was detailed in Paul A. Samuelson’s Economics, tenth edition, McGraw-Hill). It follows that lowering the ratio of land and capital to the population would also lower living standards. And this is what eventually happened as the population expanded.
On the other hand, there's the following (seen on David Friedman's web site):
That should not be astounding. This was the same period in which monarchies started becoming absolute.
In the thirteenth century, movement was to be noted everywhere: there was general prosperity and the population was increasing by leaps and bounds; popular culture was effervescing in bubbles that researchers are only now beginning to pick up. Then, in the late Middle Ages, a long term regression set in (for reasons much too complicated even to suggest in this short book), and a period of economic, demographic, and cultural retrenchment began which was to continue until the early nineteenth century. It is this epoch of decline and stagnation in the grand sweep of Western life that one might call "traditional." During this epoch the popular values and patterns of doing cultural business were nailed into place that subsequent folklorists would think had begun with the Druids.
Shorter, Edward, The Making of the Modern Family, pp. 20-21
By the way, where did all this Malthusian rhetoric come from? On the topic of immigration, many conservatives sound like a combination of Paul Ehrlich and Margaret Sanger.
The best reason to oppose open immigration was that liberals were for it. By now (considering Paul Krugman's comments on immigration), even that's going away.