I've never tried marijuana. I think I'd rather eat it in cookie form than smoke it. But I'm definitely in favour of legalizing it. It's only a "gateway" drug toward more dangerous stuff because of its illegal status. We hear about "skunk" strains with dangerously high THC levels, but that actually strengthens the case for legalization: if it's legal, the government can regulate it and remove skunk the way they regulate liquor and ban moonshine.
Legalizing marijuana will also mean legalizing hemp, a crop that could revolutionize farming in North America. It's a plant that grows like a weed anywhere and has lots of important uses, like making paper in the place of cut-down trees.
It may be true that excessive use causes brain damage. So the government should give the message: "Responsible adults, use it at your own risk."
When I was in college, I used a desk on which someone had written, "Washington owned slaves and blew dope and they won't admit it"!