A Mexican soldier stands guard as a haul of marijuana and cocaine are incinerated in the background in November 2009. Fighting among the drug cartels — and between government forces and the cartels — has cost nearly 24,000 Mexican lives since late 2006.
Jesus Alcazar/AFP/Getty Images
Some analysts say marijuana may be the cartels' greatest source of cash, in part because the Mexican gangs control the production, trafficking and distribution of the drug. The cocaine they move has a higher street value, but they initially have to buy it from the Colombians.