After the Bill of Rights had been added.
The Founding Fathers sought a government based on people's law, in the balance between tyranny and anarchy. The Articles of Confederation was too close to anarchy. The Constitution was much closer to this balance they hoped for.
For those who claim the Constitution has allowed all that is happening now, you know that isn't true. People who want power would just as quickly have ignored the Articles of Confederation.
P.S. I highly recommend the book "The 5000 Year Leap".
P.P.S. If you're going to downvote...please at least explain why.
“It is not our part to master all the tides of the world, but to do what is in us for the succour of those years wherein we are set, uprooting the evil in the fields that we know, so that those who live after may have clean earth to till." -J.R.R. Tolkien