Illegal Immigrants, Not So Illegal

My wife had a friend who waited 5 years to immigrate to join his US citizen brother to help in his brother's business (he died before being approved). While I do have sympathy for children moved against their will by their parents; they are still jumping the line after breaking the law. To say they are not competing with legal citizens for jobs because many already were working, only proves an illegal workforce is already straining the system and harming incomes. Employers should be prosecuted for knowing violating immigration laws. If 30 million illegals (by some estimates) live here and the US population is 300 million; how would their absence increase employment and reduce the 8.3%? And how is it illegals get college educations paid for