The Missouri Compromise of 1820 established a line dividing free and slave territories, admitting Missouri as a slave state and Maine as a free state, while leaving future territories to decide on slavery through popular sovereignty. In contrast, the Compromise of 1850 addressed territorial issues arising from the Mexican-American War, allowing New Mexico and California to determine their slave status through popular sovereignty. This created a contradiction, as the Missouri Compromise's fixed boundary was undermined by the flexible approach of the Compromise of 1850, leading to increased tensions over slavery in new territories. Ultimately, both compromises highlighted the growing divisions in the United States over the issue of slavery.
The Missouri Compromise allowed Missouri to be entered as a slave state. It also made it possible to create a clear line as to how the North and South states could be divided. The admittance of the state of California was the point at which the Missouri Compromise could not longer be utilized for this purpose.
it ran across the border of Mexico
James Madison does not match with the Missouri Compromise.
It gave America possession of an iceberg in the Antarctic Region, Missouri and the remaining unclaimed land in Mexico.
The acquisition of huge territories from Mexico, including California, which was too big to fit the terms of the Missouri Compromise.
It affected the enormous territory acquired from Mexico (the Mexican Cession) following the Mexican-American War (1846-48). Under the Missouri Compromise (1820), slavery would be allowed in the territories and future states south of 36° 30' N latitude.
The vast new territories ceded from Mexico invalidated the Missouri Compromise that had kept the peace for thirty years. So a new compromise had to be worked out, and this one did not last.
Yes. That Compromise worked well for thirty years, until the new territories acquired from Mexico required a new Compromise.
admitting equal number of free and slave states
it ran across the border of Mexico
There were two Missouri compromises. The one in 1820 determined the slave/free status of new states within the territory acquired from France in the Louisiana Purchase. The second one, the Compromise of 1850 did the same thing for the territories acquired from Mexico after the Mexican war.
Slavery would be legal there. But this did not apply to the new territories that were later acquired from Mexico.