The economy was not doing well, soldiers were coming home with horrible PTSD and after-shock, the great depression was going on, etc. :)
I assume by "feds" you mean the federal government. They enforce national laws. While the states can make their own laws they must do so by abiding by federal law. For example, a state cannot make murder legal.
Modern era or period refers to a time after post-classical history. It can be divided in the early era (16 Th. century) and late modern era (18 Th. century).
Some examples of historical facts in the late modern era are American, French and Russian Revolution and the Industrial Revolution.
The spread of coal-powered factories has been characteristic of the modern era because coal was used to heat buildings, generate electricity and for steam engines. It generates energy for industry and transportation.
D. The American soldiers went out on S&D missions to root out VC and destroy supply lines.
