The US constitution was written by the founding fathers in Philadelphia in the summer of 1787. This document remains largely intact and unchanged as the US constitution has both survived and worked. 

There are many merits associated with the US constitution as the constitution has proved extremely robust and adaptive. This is because the executive power has been vested in the President of the United States, which has 'survived the test of time', while Congress's power to provide for the 'common defence and general welfare of the United States' has enabled the document to be adapted to a changing society.

Another merit, is the amendment process which was devised by the Founding Fathers. Since the US Constitution was written by the Founding Fathers in 1787, it has had 27 amendments made to it which has helped to shape and reform parts of the constitution.

Demerits associated with the US constitution revolve around the fact that the eighteenth century document has not proved sufficiently adaptable to the needs and the wishes of modern US society and government. There were two main areas of disagreement between the delegates that caused debate. The first area of debate was between big states and small states. At the start of the Convention, the largest state, Virginia, proposed a strong central government based on three principles; two chamber legislature, elected by the people, with wide ranging powers, and a strong executive, chosen by the legislature, and a national judiciary, appointed by the legislature. Because such a legislature, making all the important decisions, would be dominated by representatives of the states with the largest populations, this plan was unacceptable to states with smaller populations.

The second area of debate revolved around slavery. At the time of the Convention, almost one-third of the people of the Southern states were enslaved Africans. Delegates from the southern states, whose prosperity depended on slavery, made it clear that they were not prepared to accept a constitution that restricted slavery. 

The failures of the confederation caused compromises to be reached, that shaped the US constitution and made it possible to find a balance between effective government and personal freedom that a majority could accept. 

The fact the constitution it produced has remained largely unaltered for over 200 years means that the constitutional convention is now seen as an immense political achievement.