How did nationalism help cause ww1?

Nationalism was the most important cause of ww1 this is because the war was made to show which country was the best.

''Austria was afraid of it's empire breaking up, Which would lead it to losing it's power''

Therefore, it is clear that nationalism was the most important cause of ww1 as the countries wouldn't of gone to war if they did not want to show that they were the best.

Nationalism is more important than Imperialism (Next paragraph) because none of this would've occurred if nationalism wasn't there.