I hate to rain on anybody's patriot parade, but the Founders did not have the idea that the US would endure as some wonderful place.
First, it was considered an experiment, and sometimes still is. The implication being it might not turn out.
Thomas Jefferson knew the natural progress was for government to grow and freedom to shrink. Consider also his liberty tree comment.
Even within the first few years there was at least one little crisis where (New England, I think) was threatening secession over something or other.
There were obvious violations of the 1st Amendment in the Alien and Sedition Acts.
Consider that the Framers
did not include a Bill of Rights. It took the actions George Mason, Patrick Henry, and others to get the Bill of Rights. Even Madison did not want it initially. Only after the ruckus over the lack of a Bill of Rights threatened to derail ratification of the Constitution itself, did we get a Bill of Rights.
Ben Franklin gave the closing address to the Constitutional Convention. He was thought it wouldn't work. He lent his support to the Constitution because he felt nothing better could be achieved, and that the Constitution would provide some benefit while it lasted, and that he thought he might be wrong. Actually, Franklin was too ill to read it. He wrote it, and another read it to the convention for him. You can read it at the link below. Pretty amazing stuff.
The Framers knew this was gonna be iffy. I'm pretty sure none were so unwise in the ways of the world and human nature as to hold some vision of enduring wonderfulness.
http://www.thisnation.com/library/accepting.html