In 2001, Portugal became the only EU-member state to decriminalize drugs, a distinction which continues through to the present. Last year, working with the Cato Institute, I went to that country in order to research the effects of the decriminalization law (which applies to all substances, including cocaine and heroin) and to interview both Portuguese and EU drug policy officials and analysts (the central EU drug policy monitoring agency is, by coincidence, based in Lisbon). Evaluating the policy strictly from an empirical perspective, decriminalization has been an unquestionable success, leading to improvements in virtually every relevant category and enabling Portugal to manage drug-related problems (and drug usage rates) far better than most Western nations that continue to treat adult drug consumption as a criminal offense.
Glenn Greenwald, The success of drug decriminalization in Portugal, Saturday, March 14, 2009
By the way, here in the US no drug laws existed prior to 1913 if memory serves. And best I know it's not like everyone here just became a junkie. A nation of junkies would hardly have been as powerful as successful as the US at the time.