What role did nationalism play in causing WWI?

The most direct way nationalism caused World War I was through the assassination of Archduke Franz Ferdinand, who was the heir to the throne of the Austro-Hungarian Empire. This led, on July 23, 1914, to a series of unconditional demands sent to Serbia by the Austro-Hungarian empire in the form of an ultimatum.

a   church leadership can be defined as a process of influencing other people to work together to accomplish a desired purpose.

in this case one person acting as a role model and influencing other to work as one person to accomplish a certain misson or purpose.

this can be either leading people to do the work of god