This can only work if morality is upheld.
This means no legal pornography,abortion etc.. excess wealth that leads to power over the poor for political purpose.
A democracy based upon freedom to whatever you want based upon a legal system that protects sin and calls it freedom has failed in less than 300 years
True, but you cannot legislate morality nor use a government to force people to be moral. Morality must be voluntary with the exception of the major crimes like murder, theft, etc.
A centralized global bureaucracy "with teeth" cannot maintain peace and prosperity (and charity) nearly as efficiently or effectively as local governments that allow for a wide variety of freedoms, customs and traditions (and personal generosity) within the larger secular law.
And that is the huge fly in the ointment. While I have not finished the encyclical yet (plan on it soon), in skimming I see the same problem that exists in Distributism (not sure on the spelling).
For this to work, there needs to be a powerful body governed by moral men. Other wise, it will simply be used as a hammer against adversaries.
Many good points, but while he explicitly says this is not a Utopian thing, I fear that it is in the world we live in today. There were times when such a thing could have worked.