If you actually read the treaties, while they do set firm limitations on the legal, "non-medical" or "non-scientific" sale of schedule drugs — limits that Uruguay, Colorado and Washington ignored when legalizing cannabis — they don’t otherwise obligate countries to penalize drug use. Even the 1988 convention, the harshest of the three, which instructs countries to criminalize use, still provides an out for states, allowing such laws only as they are "subject to its constitutional principles and the basic concepts of its legal system." This loophole has been used by the Dutch to argue legally for their coffee shops.
Peter Reuter (RAND), Franz Trautmann (Trimbos Institute) (eds.)
15 March 2009
This report commissioned by the European Commission, found no evidence that the global drug problem has been reduced during the period from 1998 to 2007 – the primary target of the 1998 UNGASS, which aimed to significantly reduce the global illicit drugs problem by 2008 through international cooperation and measures in the field of drug supply and drug demand reduction. Broadly speaking the situation has improved a little in some of the richer countries, while for others it worsened, and for some of those it worsened sharply and substantially', among which are a few large developing or transitional countries. Given the limitations of the data, a fair judgment is that the problem became somewhat more severe.