In recent years American police forces have called out SWAT teams 40,000 or more times annually. Last year did you read in your newspaper or hear on TV news of 110 hostage or terrorist events each day? No. What then were the SWAT teams doing? They were serving routine warrants to people who posed no danger to the police or to the public.

Occasionally Washington think tanks produce reports that are not special pleading for donors. One such report is Radley Balko's "Overkill: The Rise of Paramilitary Police Raids in America" (Cato Institute, 2006).

This 100-page report is extremely important and should have been published as a book. SWAT teams ("special weapons and tactics") were once rare and used only for very dangerous situations, often involving hostages held by armed criminals. Today SWAT teams are deployed for routine police duties. In the U.S. today, 75-80 percent of SWAT deployments are for warrant service.

In a high percentage of the cases, the SWAT teams forcefully enter the wrong address, resulting in death, injury, and trauma to perfectly innocent people. Occasionally, highly keyed-up police kill one another in the confusion caused by their stun grenades.

Mr. Balko reports that the use of paramilitary police units began in Los Angeles in the 1960s. The militarization of local police forces got a big boost from Attorney General Ed Meese's "war on drugs" during the Reagan administration. A National Security Decision Directive was issued that declared drugs to be a threat to U.S. national security. In 1988 Congress ordered the National Guard into the domestic drug war. In 1994 the Department of Defense issued a memorandum authorizing the transfer of military equipment and technology to state and local police, and Congress created a program "to facilitate handing military gear over to civilian police agencies."

Today 17,000 local police forces are equipped with such military equipment as Blackhawk helicopters, machine guns, grenade launchers, battering rams, explosives, chemical sprays, body armor, night vision, rappelling gear, and armored vehicles. Some have tanks. In 1999, the New York Times reported that a retired police chief in New Haven, Conn., told the newspaper, "I was offered tanks, bazookas, anything I wanted." Balko reports that in 1997, for example, police departments received 1.2 million pieces of military equipment.

With local police forces now armed beyond the standard of U.S. heavy infantry, police forces have been retrained "to vaporize, not Mirandize," to use a phrase from Reagan administration Defense official Lawrence Korb. This leaves the public at the mercy of brutal actions based on bad police information from paid informers.

SWAT team deployments received a huge boost from the Byrne Justice Assistance Grant program, which gave states federal money for drug enforcement. Balko explains that "the states then disbursed the money to local police departments on the basis of each department's number of drug arrests."

With financial incentives to maximize drug arrests and with idle SWAT teams due to a paucity of hostage or other dangerous situations, local police chiefs threw their SWAT teams into drug enforcement. In practice, this has meant using SWAT teams to serve warrants on drug users.

SWAT teams serve warrants by breaking into homes and apartments at night while people are sleeping, often using stun grenades and other devices to disorient the occupants. As much of the police's drug information comes from professional informers known as "snitches" who tip off police for cash rewards, dropped charges, and reduced sentences, names and addresses are often pulled out of a hat. Balko provides details for 135 tragic cases of mistaken addresses.

SWAT teams are not held accountable for their tragic mistakes and gratuitous brutality. Police killings got so bad in Albuquerque, N.M., for example, that the city hired criminologist Sam Walker to conduct an investigation of police tactics. Killings by police were "off the charts," Walker found, because the SWAT team "had an organizational culture that led them to escalate situations upward rather then de-escalating."

The mindset of militarized SWAT teams is geared to "taking out" or killing the suspect – thus, the many deaths from SWAT team utilization. Many innocent people are killed in nighttime SWAT team entries, because they don't realize that it is the police who have broken into their homes. They believe they are confronted by dangerous criminals, and when they try to defend themselves they are shot down by the police.

As Lawrence Stratton and I have reported, one of many corrupting influences on the criminal justice (sic) system is the practice of paying "snitches" to generate suspects. In 1995 the Boston Globe profiled people who lived entirely off the fees that they were paid as police informants. Snitches create suspects by selling a small amount of marijuana to a person whom they then report to the police as being in possession of drugs. Balko reports that "an overwhelming number of mistaken raids take place because police relied on information from confidential informants." In Raleigh-Durham, North Carolina, 87 percent of drug raids originated in tips from snitches.

Many police informers are themselves drug dealers who avoid arrest and knock off competitors by serving as police snitches.

Surveying the deplorable situation, the National Law Journal concluded: "Criminals have been turned into instruments of law enforcement, while law enforcement officers have become criminal co-conspirators."

Balko believes the problem could be reduced if judges scrutinized unreliable information before issuing warrants. If judges would actually do their jobs, there would be fewer innocent victims of SWAT brutality. However, as long as the war on drugs persists and as long as it produces financial rewards to police departments, local police forces, saturated with military weapons and war imagery, will continue to terrorize American citizens.