Exactly. Granted Meth is probably a lot more addictive than nicotine, but I don't see why one line of thinking should apply in some cases and not to others. If we can use the "Its my body and my life" argument for abortion, alcohol, and tobacco I don't see why that line of thinking wouldn't apply outside of those issues.

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Neither am I the means to any end others may wish to accomplish. I am not a tool for their use. I am not a servant of their needs. I am not a bandage for their wounds. I am not a sacrifice on their altars. ... I owe nothing to my brothers, nor do I gather debts from them. I ask no one to live for me, nor do I live for others. I covet no mans soul, nor is my soul theirs to covet.

Ayn Rand, Anthem.