Yes the process where Nations saw the need to work together was after the first world war, the League of Nations was established on January 10, 1920, at the initiative of the victorious Allied powers at the end of World War I. war, before Abdul'baha passed away, but the foundations were weak. Abdul'baha was aware this was not the foundation. He had already predicted where that foundation would be built.
It needed a 2nd world war, then the "United Nations" came into existence on October 24, 1945.
"...Now, more than 75 years later, the United Nations is still working to maintain international peace and security, give humanitarian assistance to those in need, protect human rights, and uphold international law.
At the same time, the United Nations is doing new work not envisioned for it in 1945 by its founders. The United Nations has set
sustainable development goals for 2030, in order to achieve a better and more sustainable future for us all. UN Member States have also agreed to
climate action to limit global warming......"
History of the United Nations | United Nations
Thus it is indeed firmly established since 1945 when it started with 51 Nations.
It is also started in the City that Abdul'baha had foretold.
"...
Abdu’l-Baha had prophetically declared in San Francisco, a third of a century before, “May the first flag of international peace be upraised in this state.” And when the cornerstone of the United Nations’ permanent seat was laid in New York City in 1949, the Baha’is recalled Abdu’l-Baha’s visionary statement thirty-seven years earlier, declaring New York as the “City of the Covenant” and saying, in an address at the Astor Hotel to the New York Peace Society:
There is no doubt that … the banner of international agreement will be unfurled here to spread onward and outward among all the nations of the world." – The Promulgation of Universal Peace, p. 125
The Baha’is, the United Nations and Universal Peace
Another sound prediction of future events.
Regards Tony