Hiring Illegal Aliens

I know it is illegal but....

Why is it illegal to hire illegal aliens?

Pres. Bush is in town talking tough on immigration. One thing I agree with him and Jeff Flake on. Let the Mexicans have jobs. I don't see how it hurts anyone, except as a consequence of other bad policies, mostly regarding taxes. Would anyone be opposed to hiring illegals if we could tax them?

Think about it. It is a silly position to take. Americans sound like the silly French and German socialists. "You may visit but you must promise not to work. It destroys our economy and steals our jobs. We are too fragile to adjust..." Blah blah blah. It is a very weak stance to take. Saying that "They are stealing jobs" is just whining.
Let everyone work. And let everyone pay for education, medical care, food, housing etc.