"How often have we heard that illegal immigrants "take jobs that Americans will not do"? What is missing in this argument is what is crucial in any economic argument: price.
"Americans will not take many jobs at their current pay levels -- and those pay levels will not rise so long as poverty-stricken immigrants are willing to take those jobs." -- Thomas Sowell
"The willingness of Americans to do a job depends on how much that job pays - and the reason some jobs pay too little to attract native-born Americans is competition from poorly paid immigrants." -- Paul Krugman
(There's something you don't see every day: A conservative and a Lefty Loon agreeing.)