Arizona on illegal immigration: The feds failed us

Arizona Gov. Jan Brewer did the right thing a few minutes ago and signed a simple new law that states it is against Arizona law for a person to be in the United States illegally.

Hard to imagine that this would be controversial, but it is. President Barack Obama (no less) opposes the law on grounds it violates the civil rights of citizens (of the United States, I presume.)

Truth is that the new Arizona law underscores the absolute failure of the federal government -- Republican and Democrat -- to protect the life and liberty of citizens by securing our border with Mexico. That's how I see it and, frankly, I'm having trouble understanding the other side of this argument.

What's wrong with a state law that says it is illegal to be in the country illegally? Assuming law enforcement enforces the laws legally and protects the civil liberties of Americans (and I think they will), where's the beef?