Radley Balko notes:
[University of Eastern Kentucky criminologist Peter] Kraska found that the number of SWAT deployments in America increased from 3,000 per year in the early 1980s to around 50,000 by the mid-2000s. That’s about 135 SWAT raids per day. The vast majority of those are for drug warrants.
Balko partially blames "the martial rhetoric of the 'drug war'":
Unlike the targets and crosshairs that ultimately had nothing to do with the Tucson shootings, the willingness of politicians to define drug prohibition policies in terms of war has had real consequencesnamely, cops who approach drug law enforcement as if American streets were battlefields. Ronald Reagan once compared the drug war to the World War I battle of Verdun. Drug warriors have described the narco-carnage in Mexico as a positive sign. One Georgia sheriff recently likened his own anti-drug efforts to the invasion of Normandy.