From a review in The Guardian of McMafia: Crime Without Frontiers, by Misha Glenny:

Glenny correctly identifies the contradiction of the Wars on Drugs and Terror, in which the illicit trade created by the former sustains the enemy in the latter. ‘If the UN is right and drugs account for 70 per cent of organised criminal activity,’ argues Glenny, ‘then the legalisation of drugs would administer by far the deadliest blow possible against transnational organised criminal networks.’