The correct answer to this open question is the following.
In the 18th century (the 1700s) the United States, conflict and compromise helped to unify the new nation in that the 13 North American colonies set aside their differences and had to work together, defending their interests against the oppression and heavy taxation imposed by the English crown.
The colonists were tired and angered for the heavy taxation such as the Navigation Acts, the Tea Act, or the Stamp Act, and the fact that they had no voice or representation in the British Parliament. This and other events such a the Boston Massacre, were causes of the American Revolutionary War of Independence, when the Continental Army led by General George Washington, defeated the British troops, and finally get independence from the English government.