The main reason the united states decided to build a canal across panama instead of nicaragua was that:
the distance to deliver materials from the united states was shorter.
the united states already had control of the land.
the land in panama had more volcanoes.
the land and building rights were less expensive.

most people were factory or company owners.

after the roman empire, the catholic church began to unify by taking on many duties of a government.

no every country is held to the same degree as others just some member countries such as the usa and germany are more economically sound so the need to show there support to all others