"You can blame W for a lot of things (and can give credit where it's due, too), but it's not the President's fault that we citizens can't rally 500,000 like the illegals can."
We are not a country of street mobs. Unlike third world Latin countries, Americans debate issues and vote for those supporting their views. Citizens with jobs, families and responsibilities do not need to compete in street theatrics with those who march because they cannot (legally) vote.
The primary reason for this is that we have a societal expectation that our elected representatives in the legislative and executive branches will well, and faithfully, represent our interests.