Marijuana Laws

In the last election, two states, Washington and Colorado, legalized the possession of up to an ounce of marijuana for recreational use. Since this conflicts with federal law, it remains to be seen if it stays in force or gets overturned. Now, from what I know, marijuana isn't that dangerous a drug. I take it to be on the same level as alcohol. Since alcohol is legal, I see no reason why marijuana shouldn't be legal as well. Other drugs like heroin, cocaine, meth and such are far more dangerous both physically and psychologically and should remain illegal. If it hasn't been done already, a comprehensive study should be done on marijuana. We need to know if it has legitimate medical uses or not. We also need to know about any and all detrimental effects it has on the human body.