One hundred years after the first international drug control treaty was signed the failure of the "war on drugs" is indisputable. In Europe two distinct trends are emerging around how countries are choosing to tackle drug policy; a punitive, criminalization approach--which is failing dramatically and expensively--or one based on scientific evidence and harm reduction--which is bearing fruits.

Punitive, law enforcement-focused drug policies are usually an outcome of unrealistic expectations, prejudice and lack of knowledge. Contrary to ample evidence, it remains many politicians' belief that harsh drug laws deter people from experimenting with illicit substances, lower demand for drugs, and help the police to apprehend drug suppliers. These misguided assumptions are increasingly questioned and the Czech Republic is emerging as a global example of an effective, evidence over ideology approach to drug policy.

In the post-Soviet 1990s, greater personal freedoms in the then Czechoslovakia led to more widespread and visible drug use and drug markets. Czech politicians felt the urge to respond to what they believed was a new social problem. By 1998, a few political parties rode a wave of popular distaste for the drug scene, and the Czech government was pressured to change its liberal drug policy. The modification, although unfavorable, was slight. The new law stated that the possession of illicit drugs in amounts greater than a certain threshold amount should be criminalized. The legislators did not, however, specify what these limits were.

In an unexpected move, the Czech government commissioned a scientific evaluation of the impact of the new law. This rarely happens when drug laws are made harsher. "According to the study, criminalizing drug possession did not have the desired deterrent effect, did not have a health benefit, and was economically costly to society," concludes a newly published report on Czech drug policy by the Open Society Foundations.

The results of the evaluation of the law were widely covered in the media and positively influenced subsequent drug policy decisions in the Czech Republic. This is even rarer. Unlike many other countries in Central and Eastern Europe, the Czech Republic recognized the need for ready access to health and treatment services for drug users. Due partly to good availability of needle exchange programs for people who inject drugs and access to medication-assisted therapy for drug dependence, HIV prevalence among drug users remained low in the country.

Elsewhere in Central and Eastern Europe, a former head of state has acted on his reflections on the kinds of lessons that come from the Czech story. In May, Aleksander Kwasniewski, a former president of Poland, joined the Global Commission on Drug Policy and became the first former President from this part of the world to be affiliated with that body. The Global Commission on Drug Policy advocates for evidence-based drug policies, including the decriminalization of drug use and possession of drugs for personal use, unrestricted access to treatment for people dependent on drugs, and wide provision of services that prevent drug overdose and public health crises such as HIV epidemics.

In an article published in the New York Times, Kwasniewski discusses his decision from 2000 to criminalize the possession of any amount of illicit drugs. At the time, Polish politicians believed that a harsh criminal approach would solve "the problem of drugs." But drug dealer arrests remained low, while the number of individuals charged with drug possession skyrocketed from 2,815 in 2000 to 30,548 in 2008. The law affected mainly young people, and--as the Czech study on criminalization indicated--was costly. The statute cost the Polish taxpayers over $25 million annually.

Kwasniewski calls for the opening of a debate on evidence-based drug policies in Poland's neighboring countries in Central and Eastern Europe, especially in Ukraine and Russia where a HIV epidemic is alarmingly fast growing.

But Ukraine and Russia are not alone in having ineffective and overly harsh drug policies. A year ago, the Hungarian Civil Liberties Union warned the international community that the national government of Hungary was planning to withdraw from its progressive and well-balanced drug strategy, adopting instead the unattainable goal of a drug-free country. First steps have already been taken, with harm reduction programs being closed down due to a lack of state funding.

Evidence on effective drug policy is vast compared to what the signees of the International Opium Convention had at their disposal in 1912. It's time now, a century later, to apply this evidence, eschew ideology and learn from success stories like the Czech Republic.

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