Nationalism was the most impactful in World History. This is because it is a movement for justice and national achievement. As well as the freedom of choice. Nationalism has given people a new thought of unity with the nation and with each other. Even though nationalism caused violence and division, it was a key factor in helping the nation grow. From this, the country has grown stronger. This is shown by world wars and the country coming back from war in one piece. Nationalism produced the constitution, which gives the government power. Nationalism gave the U.S. the document that the government is based off of. Nationalism can be impactful because it is a sense of identity, unity, and pride among people who share common history, and values.