The gateway drug myth has been around since your parents were smoking pot. It's old school propaganda that has been dis-proven by multitude of independent studies in over a dozen different countries, all with different drug policies.
http://scholar.google.com/scholar?start=20&q=marijuana+gateway+effect&hl=en&as_sdt=0,10&as_vis=1
The #1 contributor to the gateway effect is socioeconomic status. The poorer you are, in the poorer area you live, the higher chance you will use illicit drugs. How many people who know make over $50k a year use crack? How many of them smoke pot? Why does this gateway effect only happen to people in the ghetto or trailer parks?
That's the problem with most issues today. They require people to study and investigate it independently instead of relying on 60 year old propaganda passed down from parents and teachers, which then infiltrates the next generation of politicians who push the same archaic agendas.
We should be taxing all the fucking stoners and giving that money to our teachers and cops. Instead of taking away their benefits like we are now.