The last if not the most important major development in the Constitution during the federalist stage was the establishment of the Bill of Rights. The Bill of Rights are the first 10 amendments that were originally created as a compromise between the federalists and anti-federalist, as the anti-federalist strongly believed that US citizens needed protection from the central government and that these protections should be neatly and specifically spelled out in the Constitution. The anti-federalists flat out did not want anything to do with this new social contract that the founding fathers were drafting up because they felt it gave up all individual rights of citizens, so they compromised with the federalists in order to form the current Bill of Rights. As the constitution was still in the earliest parts of its developments, a large conflict would change the course of our nation for all of eternity. .
The next stage of constitutional development is the Civil War Era, or it really should be called the Post-Civil War Era since everything significant that happened to the Constitution occurred after or as a result of the Civil War. After the Union was officially victorious in the war in 1865, President Lincoln made it his first order of business to outlaw the sole activity that the war was being fought over, which was the act of slavery. Lincoln and Congress worked diligently to pass the 13th, 14th, and 15th, amendments throughout the years 1865-1870, each with a different role in suppressing slavery in the South. The 13th amendment simply abolished slavery throughout the US except for as a punishment for crime. The 15th amendment was known as the "black suffrage" amendment; so in other words this ad on to the Constitution prevented the discrimination of voting based on race or color. Now 14th amendment was easily the most important of the three and this was because there were three different parts to it.