I believe in legalizing marijuana. It's safer than alcohol, and keeping the safer drug illegal, while making the more dangerous one legal, is unscientific and illogical.
But past that, I think any drug should be legal. If you take a drug, it doesn't affect me. By what right do I stop you? If you steal to support your drug habit, or commit assault while high, then obviously that requires retribution, but the problem is not the drugs; it's the robbery or assault.
However, I should not have to buy you drugs. That's not fair. Thus, I don't support legalizing drugs for those receiving welfare or unemployment insurance. (Also, I obviously don't support welfare or unemployment insurance. Private charities do it better. Look at how successful private charities have been at transforming people's lives, and how successful government welfare has been at ruining them.)