Which national event precipitated the rapid expansion of police departments across the united states? the colonial settlement in jamestown, virginia the civil war the terrorist attacks of september 11, 2001 the vietnam war?

It was not until after the Civil War in the year 1861 – 1865. The United States gradually started to see several cities accept the police department model like in New Orleans in the year 1852 and in Baltimore in the year 1853. However, it was not until after the Civil War that the United States saw a rapid expansion of police departments through the country. Policing in America at that time did not look a lot like the modern policing nowadays. 

a, he promoted disarmament