Sectionalism is when people care more about the part of a place they live in than the whole place.
Sectionalism can make people think of arguments and not working together.
Examples:
Sectionalism can make people not want to help each other.
The sectionalism between the two towns made it hard for them to agree.
The sectionalism in the country made it hard for the leaders to agree on new laws.
The sectionalism between the two groups was so bad, they couldn't even talk to each other.
The sectionalism in the school was so bad, they split into two schools!
The sectionalism in the town was so bad, they split the town in two.