Although the intent of a 'War on Drugs' may have been to target drug smugglers and 'King Pins,' of the 1,558,862 arrests for drug law violations in 2019, 86.7% (1,351,533) were for mere possession of a controlled substance. Only 13.3% (207,329) were for the sale or manufacturing of a drug. Further, 35.0% of drug arrests in 2019 were for marijuana offenses -- a total of 545,602. Of those, an estimated 500,395 arrests (32.1% of all drug arrests) were for marijuana possession alone. By contrast in 2000, a total of 734,497 Americans were arrested for marijuana offenses, of which 646,042 (40.9%) were for possession alone.
"Crime in the United States 2019 - Arrests," FBI Uniform Crime Report (Washington, DC: US Dept. of Justice, September 2020), p. 2, and Arrest Table: Arrests for Drug Abuse Violations.
"Crime in the United States - 2000," FBI Uniform Crime Reports (Washington, DC: US Government Printing Office, 2001), p. 216, Tables 29 and 4.1.