The importance of nationalism had to do mostly with the ability of any given country to get things done and overcome problems. A country with a strong sense of nationalism may have fewer social problems and may be more able to deal with a crisis than one where citizens do not care as much about supporting their government. One can see that from era to era, nationalism played a big role in the rise of every country we see as a “strong nation” today. People usually start talking about nationalism in history starting in the very early 20th century.

Hope this helps.

Nationalism has also effected history. Without people being so proud of their countries, many soldiers wouldn’t have the esteem to carry on. In Stalingrad, those Russians carried on through the long cold winter. Though many died, some still made it. Archduke Franz Ferdinand was assassinated by a Serbian nationalist–and this helped spring WWII up, along with German nationality. It motivates people and gives them a sense of power. It’s a very strong force to reckon with.

simply put, nationalism is a social “force” that can motivate people to take action. it can be used by unscrupulous people to manipulate others, including very large groups of people.

you can observe an analog of nationalism-based manipulation at work at any sporting event (larger the better). teams/cheerleaders/commercials/mcs/ do their thing and people respond.

hope this helps.