are there ways to design programs so that may be the uniteunited states get a littlet more of the benefits of immigration and a little less of the negative costs that you talked about or is it really this zero-sum trade-off that you suggested an answer to the previous question? >> guest: it all depends on what the numbers look like. let's take the numbers available for face value. they indicate the conclusion of the labor market increases by $50 billion a year. the national academy of sciences reports that in the short run the fiscal burden is at least 50 billion. so the average worker it hides below the distribution even though the pie might not be much bigger or much smaller it is different and that is really the problem. would we be here right now having this problem if immigration the last 20 or 30 years where every american was made better off? the fact of the matter is no we wouldn't be debating it at all we would be happy with the whole scheme of things we developed over the last decade or so some people are left behind and needs to be addressed. in the last chapter of the book we t