How the National Guard Got Its Riot-Control Role - LA Progressive

"The modern National Guard evolved from Colonial-era militias.Although many Americans are skeptical of any military response to civilian unrest, the National Guard is widely seen as a reliable peacekeeping force.Because of post-Revolutionary fears over the cost and potential tyranny of a standing army, the Constitution authorized citizens to form militias that would “execute the Laws of the Union, suppress Insurrections and repel Invasions.”Subsequent militia acts confirmed state authority over the militia with responsibility as a national military reserve for defense and peacekeeping. By the 19th century, local militias were almost everywhere, but they varied widely in mandate and quality."