Just throwing a bill of rights with Libertarian twists at the framework is not enough. The success over time in the US, which now appears to be eroding, was the Judaeo-Christian underwriting. It is well documented that the framework provided by, the recognition of, and commitment to the religious/spiritual ethos of that framework ignited, early on, the American experiment. That framework carried it far. Now as the spiritual underpinnings are being replaced, the advantages are slipping away.
If there is no foundation such as this, the society will not long endure. Will most likely tend toward socialism and authoritarianism.