AMERICANS are wide awake to the border fiasco. Unfortunately, virtually all of our politicians (except Representative Tancredo) pander to those in corporate management who are more interested in cheap labor than they are in the integrity of the US workforce and US citizenship. Add to that they don't mind one bit that the US workers (many unemployed or underemployed because on non-citizen labor) subsidize this "cheap" corporate labor through taxes paying for services.
If 911 wasn't enough to close the border for a while and figure out who should and who should not be here, expect nothing from those in charge.
In my opinion, support for border control is slowing building. Give it ten years.
As for SARS, once it hits Mexico, this will strengthen support for border control, but will still not be enough to make it a reality. I'm basing that on an expectation that Mexico will manage to institute effective quarantine and infection control when needed. Plus, even if they only do a middling job, the liberals will say that legal entrants from Mexico to the US might also have SARS. Which will be a complete crock, since legal entrants get better medical care while in Mexico.
Which is why those in charge must be defeated when they run for reelection.