Both, though it's is more complicated than what can be summed up into a yes/no answer. Cotton subsidies, for example, have us being able to pay less for cotton products but it leaves only pennies a day for African cotton pickers, many who end up leaving Africa for go to Europe where they can actually do better for themselves.
So, though this immigration involves legal and illegal immigration, it is policies abroad that drive it, and these policies that must be addressed before any meaningful immigration policy can happen.
Then why do I see so very few non-whites in school? Why do I see hardly any of them whenever I tread into the office/corporate environment? Why is it that studies have shown that applications that "look black" (as do applications that come from females) land fewer interviews and jobs than applications of white men?
And it's not just jobs and education. Around here, if you even look like you came from Mexico, many people are going to assume you are here illegally, you are a bad influence, and that you need to "go home". The state senate even tried to pass a bill making English the only language allowed in government buildings (never mind the fact our American English contains a sea of foreign words or that Indiana does alot of business with the Germans and Japanese). If you are black, then it is not at all uncommon for store employees to assume you are there to steal once you walk in.
