The Missouri Compromise was enacted in 1820 and it was the legislation that allowed the inclusion of Maine and Missouri as a free and a slave state respectively, hence, maintaining the existing balance of power between slavist and abolitionist states in the US.
It reshaped the border with Mexicoand set the playfield for the subsequent annexation of Texas (former Mexican territory) and the Mexican American war that would take place between 1846 and 1848.
