Milton Friedman, Nobel prize winning economist — and one of my personal idols — was among the most influential libertarian thinkers of the last century. Friedman was primarily a consequentialist, meaning he advocated libertarian policies based on the fact that they work better. Such an approach has the great advantage of political effectiveness. If you can demonstrate that greater freedom also leads to better economic results — better solutions to the Roti, Kapra aur Makaan issues — you will have a much easier time swaying the public to your point of view.
However there were some issues were Friedman advocated for liberty on purely moral grounds. The video below — one of Friedman’s last interviews — is a wonderful example:
This is not to say that there is no consequentialist argument for drug legalization — on the contrary, it is perhaps the finest candidate for such analysis. Hell, even Barack Obama accepts that the war on drugs has been an utter failure. The reason, I think, that Friedman took the moral path here is that some things are just too fundamental to leave to utilitarian analysis. They are worth fighting for their own sake, discounting everything else, for they go to the heart of human existence.