The Great Depression put paid to the Prohibition; the Great Recession might well do the same to the War on Drugs. Finally it comes down to the money, the state would rather have the taxes than the jail time served. When serving politicians are talking about legalisation there's only one way this can go. Glad to see there's some practicality and realism behind the thinking, which makes it more likely that this will come to pass.
In the words of Vicente Fox "Legalisation does not mean that drugs are good…rather we have to see it as a strategy to strike and break the economic structure that allows mafias to generate huge profits in their business, which in turn serve to corrupt and to increase their power"