Chinese Exclusion Act: Questions

What rights should immigrants or foreign laborers have under American law? Should the Constitution be altered? Should the 14th Amendment be expanded?
Was the Chinese Exclusion Act or a law like it a good idea at any point? When? If not, how can you address foreign labor crowding a finite job market?
What sorts of lingering effects can a law like this have, both to a Chinese-American population and to relations between China and the United States?
Should immigration be restricted in terms of ethnicity or race? Religion? Political belief? Any criteria you can think of? Why or why not?
Is it ethical to use a population of people for cheap labor, as Chinese immigrants were used on the railroad, and then enact measures to keep more from immigrating? Why or why not? Do ethics like these have any basis for laws?
The United States often finds itself at odds with the lofty principles espoused in the Constitution and political and economic reality. When this happens, which is more important? What's more important in the case of the Chinese Exclusion Act?