The prototype or ur original sin of our political system was- and remains- slavery. As little as this may be understood, it is common to make obeisance to this fact.
Today, however, we also labor under a second 'original sin'- our failure to grant statehood or citizenship to the members of our 'empire'.
This was the rock on which the Roman Republic foundered. The Romans, having formed their government of tribes, could not figure out how to admit to citizenship people who were not born into the tribes. For our part, we have been declining in intelligence to the point where we can't figure it out either.
Perhaps the US would not survive if we offered statehood to the Puerto Ricans and territorial status to the Iraqis. 'Perhaps' is still better odds than the 'won't' we appear to be heading for today.
It is a common misconception that because governments are formed of words, they will still keep working even if a few parts are missing or broken. In fact, a government will continue to function in those cases- but it won't be the one the words describe, and it won't do what the words intended.
The fault lies, not in our Constitution, but in us.