A MEANDER ON IMMIGRATION
It appears all the participants on the thread are agreed that the moderator's question about the electoral implications of hispanic immigration are not worth discussing and the value of that immigration is.
One ought take exception to commenter Bob Buckles suggestion that a guest worker program be erected. This is simply socially corrupting, inasmuch as a foreseeable if not certain result will to create an unintegrated and permanent servant class. This has been the result of guest worker programs in Germany and Switzerland, and it is not a desirable social destination. If we maintain one principle, it ought to be that in this country, we do our own work. (A corrollary of which is that - in whatever numbers - people are invited to settle here, not merely to work here).
The economic benefits of immigration have been alluded to by others here, and are predicted by certain neo-classical models of the labor market. The economist George Borjas has attempted to quantify the benefits to the extant population of immigration flows given current welfare policy. I am working from memory, but as I recall, they amounted to about 0.1% of Gross Domestic Product per year. One might suspect that the net benefit is thus rather sensitive to adjustments in public benefit levels. Dr. Borjas was (and may still be) an advocate of immigration policies designed to favor applicants who bring a certain quanta of human capital with them (comparatively common among East Indian immigrants, but not Mexican immigrants).
Commenter Nick Peters has refused thus far to credit Latin American societies for their actual achievements, most especially over the last quarter century. "CoyoteBlue" wishes to lay responsibility for Central America's woes at the feet of the United States. Both are in error. These societies, which have been sovereign for more than 180 years and were in formation for 300 years prior to that, have their own internal social dynamic and institutional arrangements. Central American land tenures, educational systems, military cultures, and elite attitudes have been what they have been. For the United States to have altered them substantially at any time since we achieved a sort of hegemonic position in this hemisphere (ca. 1898) would have required occupying these countries and imposing a sort of 'MacArthur regency' upon them, a recommendation that would sit rather ill with the usual complaint the American foreign policy has been too intrusive in Latin America.
Nick Peters' animus aside, in making immigration policy, we are considering the effects of the movements of large numbers of people and, in describing these effects, cannot avoid the use of aggregate statistics. The posited benefit to productivity noted above is one such statistic. The differential in crime rates between the longstanding population and a selection of immigrant groups is another (and I would refer commenter "DC Lawyer" to Heather MacDonald's articles on this question in City Journal on this point). You could posit that the unhappy social statistics in question arise not from an abiding disposition within the immigrant population in question, but from factors correllated with those which induce people to migrate, or arise from some aspect of the interaction between immigrants and host societies; however, unless the aetiology of the problem is such that it can be neutralized by effective social policy in the receiving country, social pathology among immigrants and their children is a cost that will have to be weighed in assessing immigration policy.
That is, unless it be your contention that it is illegitimate to do so. Contemporary political etiquette has it that one cannot properly make certain sorts of actuarial calculations based on certain sorts of data; that one must refine one's categories of inspection. If one concedes this, one could properly insist on two provisos:
1. That such a principle applies both to data favorable to and data unfavorable to what Thomas Sowell has called the "mascot groups" of the intelligentsia;
2. That all acknowledge that the more refined and rococo a public policy is, the more difficult it is to implement with regularity.
Defenders of a liberal immigration regime are commonly dismissive of enforcement efforts. However, if the civil service is to be deemed incapable of doing something fairly crude (such as building along the Rio Grande a high cement wall topped with razor wire), it is difficult to see how consular officials and others will be able to do something as refined as reliably discern whether applicant x will or will not be an asset to the country (never mind the folks who cannot be bothered to apply within the law). Alternately, advocates can simply deny the social pathology (and various other considerations), deny the legitimacy of discussing these, or offer that the onus for the problems is on the host country who must accept the problem like a dose of salts (or generate yet more jobs for aspirant social workers in the course of various schemes at amelioration).
The question has been posed as to what social problems (bar labor recruitment in a modest selection of industries) are ameliorated by immigration. That in turn depends on what is your understanding of just what constitutes a social problem.
Some years ago, Michael Lind (a journalist favorable to the Democratic Party but skeptical of immigration) reported that he had had a discussion with a Democratic Party strategist where the man had revealed his conception of what was a social problem: the failure of the Democratic Party to mobilize a sufficient fraction of the (caucasian) working class, for which the solution was building a base among hispanics (by importing more hispanics). You have also extraparliamentary politicians and educational and social-service apparatchiks who could do with a larger constitutency.
Apart from these, you have folk for whom mass immigration may have certain psychological benefits, either in the aesthetic realm (think of people who speak of 'gorgeous mosaics') or in allowing them to think well of themselves (most particularly if the segmentation of labor markets and urban settlements makes of it that others pay any bills which may come due).
I may be in error, but I cannot shake the impression that common norms and common celebrations are frequently done away with or diluted with the excuse that "In our increasingly diverse society, we can no longer insist that....", etc.; that our immigrant populations are being used as an excuse or as infantry in a domestic kulturkampf in which they themselves have no true stake; and that many in our word-merchant sector, if carefully questioned, would reveal that as far as they are concerned the problem in this country is the vernacular culture and social attitudes of the large mass of Americans of the working class and the common-and-garden bourgeoisie who have no strong ethnic consciousness. The problem, baby, is you.
For my own part, I wish to live and die in a country that is content simply to be, composed of those born here and those who settle here to be with us as we are a people with whom they feel an affinity; not an ideological construct ("first universal nation"), nor a toy theatre for the fulfillment of someone's social fantasies, but a country, content simply to be.