"… the preservation of the sacred fire of liberty, and the destiny of the Republican model of Government, are justly considered as deeply, perhaps as finally staked, on the experiment entrusted to the hands of the American people."
George Washington’s First Inaugural Address
The Constitution was designed largely according to the ideas of Montesquieu and John Locke. Following Montesquieu, it specifies the separate duties for each of America’s three branches. Following Locke, it limits the government’s powers so as to protect individual liberties.
Its ability to do the latter function has faded rapidly since the New Deal. For example, most of the Bill of Rights remain de jure in force but are de facto void. This can be easily tested by a Lexis search of successful attempts to use them in litigation. You will find almost none.
At some point in our future the Constitution seems likely to become a purely procedural document, much like that of the former Soviet Union, and equally effective at preserving our liberties. Our rights will exist only on the sufferance of the government and our ruling elites. This is already true in the UK, as the “unwritten constitution” protecting the “rights of Englishmen” has blown away like smoke in the wind.