If marijuana is a/the "gateway" drug... then WTF does that make tobacco?!?!?! Seriously. You've never heard of anyone who does coke/heroine who doesn't smoke weed?? Well, do you know any that *don't* smoke tobacco?????? Come on. This is the most lame argument ever. And honestly, the only reason marijuana makes coke/heroine/meth/crack/etc more easily accessible is, as others have already said: because its illegal!!. If you could walk into Walmart or any old gas station and buy a joint or 5, then that takes that whole equation out.
Of course, IMO, crack, heroine, coke & the rest should be legal too. Because, lets be honest here, the amount of those drugs that come into the country, if everyone was a real hardcore good-for-nothing addict who did them, well, there wouldn't be too many folks sober enough to go to work everyday!! The vast majority of folks who do coke, heroine, etc (and yes, I know/knew lots of people in college who did, and can honestly say I've done coke & acid & mushrooms & a ton of other stuff too, but somehow I'm still a functioning adult, crazy huh?) are just as responsible as you and me, your brother and parents. If we made them *ALL* legal and we put sane restrictions on their use (no driving while high, etc), taxed them and provided people with free drug rehab for if/when they want help getting off them, we'd save BILLIONS in law enforcement, and make BILLIONS more in taxes. Not to mention totally destroy the entire underground markets both here and abroad, cut off funding for the huge drug cartels, gangs, etc & thus lesson the insane amounts of violence being caused by drugs both here and abroad, thereby saving ourselves even *MORE* money in law enforcement.
But of course, its way easier to blame all the coke/potheads/heroine/meth/crack addicts of the world for all the violence and money being wasted on them being illegal. Its way easier to just keep the status quo and keep filling up our prisons with thousands of people who are really doing nothing wrong. Way easier to just pretend like these things are the most evil things ever invented (ignoring the fact that most of them have been around for thousands of years and ingested by billlions of people and yet the human race has somehow managed to survive...), and we should treat anyone who uses them like crap.