U.S. President Donald Trump (seated) holds up his signature on the founding charter during a signing ceremony for the “Board of Peace” at the World Economic Forum in Davos, Switzerland, on Jan. 22. Chip Somodevilla/Getty Images When nations decide to create international organizations, they usually take some time to work out the details. The United States and its allies spent four years gradually laying the groundwork for the United Nations during the Second World War.