The rainy day is a symbol of life. The idea behind it is that life is like a rainy day because rain represents bad things that happens to you. The poem points out that we shouldn't be miserable because of it because even when there's rain, there's always sunshine behind it so just keep calm and carry on with life and things will get better.
Im pretty sure its c. England and France:)
The main goal of not having a non- violent resistance is so people can protest without having an violent and hurting others and cause civil war.
A trade that involves more than one state, and that is, under the constitution, a proper subject of federal law