has illegal immigration already "imploded" the middle class? if anything, their low labor costs have prolonged the existence of the middle class through the past 30 years.
ont he flip side, bringing people here legally and having them join the tax rolls, start businesses legally, pay a living wage to their workers, and provide effectively for their families would BOLSTER the middle class, much like the experience of many other immigrant groups in the US. (see asian, african, indian, and arab communities)