Libertarianism is sort of like Marxism
I don't see any logic or reason in this post at all. You are somehow melding the divergent positions held by libertarians and liberals, and then assigning the blame for those positions to libertarians. That's silly.
Libertarians don't want any expansion of government, and want it dramatically reduced in many areas. That is completely consistent with the idea of ending drug prohibition, where government involvement does some of the worst damage, causing the cure to be worse than the disease, and destroying civil rights along the way.
Surely when drug policies are changed, the coalition of libertarians and conservatives will prevent the result being a dramatic expansion of the welfare state. There's absolutely no tangible reason to believe that liberatarian efforts will further the positions of the Democratic liberals.
The point is abundantly logical. You would assume a vaccuum of philosophy...a perfect world approach, if you will. I understand the 'theory', but look at the facts, eg., tobacco and OxyContin.
The fact is, the door libertarians want to open, would open the door for an expanded government and more dependency programs...you just can't separate the two.