Frankly, I don't know why the elected officials can't seem to get anything done right.  The proposed Immigration bill is a classic example of a good idea gone awfully wrong. 
I have heard the pundits commenting for some time that we aren't enforcing the laws already on the books.  Why is that?  Are the existing laws bad?  Are they impractical? OR is the system broken and are we possibly too lazy to try to make it work.  I have yet to hear one of our elected officials say "let's enforce the existing laws for a change." 
Instead, Washington, in their ulitmate wisdom, comes up with another attempt to solve a problem.  True to whom they are, rather than a simple solution that might work, they come up with an overly complex system that, at best, might stem the flow of illegal immigrants for a short while.  BUT, for those who can gain the support of this overly hispanic proportion of immigrats, could gain a voting constituancy that will last like the Black populations' loyalty to the Democrats. 
As I alluded to, the politicians could have come up with a much simpler solution that has a higher probability of working and would cost very little to enforce and maintain.  The real immigration problem is that there is a monetary incentive for both the illegal immigrants and the people who employ them.  Remove the incentive and much of the problem wiil be solved.  People cross the border because there are jobs.  If the government charged a fine to the employers of illegals in the tune of $25,000 per individual (or more) and rigorously enforced it, the financial benefit of low-cost undocumented workers would be offset by the high cost of defense and potential fines imposed on those employers.  Let's face it, it would only take a few high profile legal actions by the government for companies to take notice and change to happen. 
Will this solve the issue?  No, but it would be far more effective than Congress' current attempt.