There are all sorts of words to use to describe the mess the United States has turned into and keep in mind the United States is not America. America is where we live, it is outside on the porch under a summer sky; it is the used car in the back and the fridge on the porch; it is bug-zappers dangling from the post. The United States is a political construct, a simple agreement between long-dead ancestors.
To the extent that the Constitution arranged the agreement and sought at the same time to set out some ground rules as far as what the federal government would take care of (mostly external issues at the time) and what states would take care of, it worked, initially. Apparently, as long as no one ever questioned it, it continued to work, but when Bill Clinton (as Pete at WRSA pointed out) violated the oath with the absolute challenge to be stopped, the gig was truly up. What we have had since then is a sort of building police state.
What is the technical moment when the Constitution failed? Maybe that goes as far back as Theodore Roosevelt when he decided that it would be a good idea to occupy huge swaths of the Western states. Make no mistake, these are not states in the same way another state might have 3-5% federally-owned land somewhere as an island in the mass of privately-owned land. Western states are between 35-85% federally-owned lands. That is an occupation and I often refer to the Western states as the Occupied States of America.
Definitely, the Constitution had failed by the time Woodrow Wilson was supported by all of the big interests in oil, steel, railroad and banking. Having recognized how detrimental a president could be after Roosevelt leaned on these interests, they were going to have nothing to do with a "trust buster" like William Jennings Bryan and I am not saying that Bryan would have been any better, he had his own problems. It was a time of big unions and big corporations and the battles taking place between them, so going whole commie at the time might not have been the best move, either. It was a time very much like this one, where there are no good alternatives, the distant powers figured out that it was easier to buy a president than to ward off the federal government and America has never been the same.
But, the United States is not America. The land will live on beyond this political construct and the people will live on beyond the United States as well. This is OUR government, it is not theirs. We have let them run things and they have run them off a cliff. The Constitution survived as long as it could, perhaps. If it had the power to repair itself, it would have. If the people we have elected to office had any reverence for it at all, they would repair it, but it should be obvious to anyone paying attention that they are incapable of doing anything for the people. The people have been relegated to supplying the cash for their boondoggles at the threat of prison. I don't care how beautifully one writes the 16th Amendment into law, it is an abomination. It was passed and it was ratified and it was the biggest mistake the people of that century ever made, but there is no reason for us to obey it.
We are at that place in America where no agency of the government is going to abide by ANY of the Amendments to the Constitution that we do not defend with our lives and our firearms. Do you really think the Second Amendment would have survived without all of those unwilling citizens out in the hinterlands that have demonstrated that they will put up a fight? This nation would have long ago caved into the demands of a dictator were it not for that.
The real question is this: If you cannot preserve the ideals of individual freedom and free market trade with your neighbor via this political construct, how many collectivists do you have to kill to finally be left alone?