And of course the historic reduction in mortality is a great boon to humanity which all people of good will desire to maintain and improve. Admitting people from abroad is the only possible palliative. If immigration had been at the late 1980s level throughout the 1940s through 1970s, the gain to the labor force would have much about the same as if births had been at the baby-boom level. And if immigration had been even half the rate relative to total population that it was before World War I, or had been at twice the 1980s level, there would have been no deficit at all. Immigration's budget benefit to natives stems from the difference in age composition between the native population and that of each immigrant cohort.
Immigrants tend to move when they are young and near the start of their work lives.
Moreover, even the small number of immigrants who are elderly are not eligible for Social Security. Therefore, each cohort of new immigrants contributes substantially to reduce the Social Security burden of natives, in proportion to its numbers. Clearly not, for two reasons. First, the impact of this year's immigrants on Social Security perhaps thirty years from now properly has little weight in the overall economic assessment, because a dollar to be received or paid out in thirty years is worth little now when discounted at even a modest rate. Hence there is a one-time benefit to natives because the immigrants arrive without a generation of elderly parents who receive Social Security.