Compared to the American founders, did Robespierre have a different view on human nature? Why did he turn to terror and violence to eliminate evil factions (with the assumption that he and his allies were inherently virtuous), as opposed to accepting the inherent evil in human nature and thus adopting a system of checks and balances to counter the evil of factions, as the Americans did?
An important thing to know about the American over the French Revolution is that of their philosophical origins. The American Revolution is very much focused on the political philosophy of John Lock, in particular his Second Trestise of Government. This philosophy was focused namely on property rights and the rights given and expected from a government. This is very much a major influence of the American Constitution, which has strong emphasis on rights by the State and protection of property.
The French Revolution is heavily influenced by the philosophy of Jean Jacques Rousseau (especially in the Jacobin circle) and his Social Contract. This is a very different form of government where rights are given to citizens but the rights are dependent on the contract the people make with the government. More focus is placed on the individual rights than the individuals property. Further, Rousseau would strongly favor a government that forced ideological purity, arguing in favor of a democratic unity in agreement going so far as to suggest that people be forced to agree if they disagree with the whole or be cast out for causing problems.
It must also be noted that Robespierre would walk around with the philosophies of Rousseau during the day, often quoting him in his orations. If anything, Locke had little influence during the more extreme parts of the French Revolution.