The answer to the question: Why would those who started the French Revolution and created the famous "Declaraction of the Rights of Man and of the Citizen", say that the revolution was not successful, would be, that despite the document and what it said, how it established the rights of people, their freedom, and sought to initiate the passage from absolute monarchy to democracy, the truth was that in France, this Declaration did not change their reality, especially not in government style. This means, the French went from being ruled by King Louis XVI, to being ruled again by the military dictatorship, and later kingship, of Napoleon Bonaparte.
The "Declaration of the Rights of Man and of the Citizen" was among the first documents ever created where the civil rights, and civil liberties of people, as well as the ideal of democracy vs. monarchy, was set down in paper. Set by the French National Constituent Assembly, in 1789, after the French Revolution, its intention was to establish the framework that would now rule the fates of the French people, who were supposed to be now free from violence, the violation of their rights, and from the absolute monarchy. In reality, after the Revolution France did not have a simple passage from confrontation into peace, and in the end, their goverment passed from being led by Louis XVI, to the hands of Napoleon Bonaparte, who assumed the control of a military dictatorship, and would later be crowned as emperor. So the changes proposed by the Declaration, were in truth, not met, until much later.
Number 3. Dred Scott v Sandford was essentially the Supreme Court saying to anti slavery states “your compromise doesn’t matter” and completed regressed any progress to abolishing slavery by declaring African Americans could NOT be citizens of the US, and that abolishing slavery was unconstitutional. This obviously led to some tension and an eventual civil war. Hope I helped!
Constitutional laws will stablish the regulations for local governments, states and the federal expressing also the citizen's rights. It deals primary with the governmental powers (the branches of executive, legislative and judiciary) and the most fundamental rights of the citizens, the civil rights (e.g. right of freedom from discrimination) and civil liberties (e.g. Freedom of Speech; Protection from Self-Incrimination; Due Process of the Law and Right to Trial by Jury for Criminal Charges).