Anti-Pinkerton Act of 1893

The Anti-Pinkerton Act was a law passed by the U.S. Congress in 1893 to limit the federal government's ability to hire private investigators or mercenaries.
The Anti-Pinkerton Act is contained within and purports to specifically restrict the government of the United States from hiring employees of Pinkerton or similar organizations such as the modern Blackwater.
The first published court case interpreting the Act, in 1977, held that the intent of the Act was in reference to Pinkerton's activities at the time, offering quasi-military armed forces for hire in the context of strikebreaking, "and therefore had little application" to the current organization.