The period from Reconstruction through the early twentieth century was a time of contradiction, transformation, and regression for many Americans that is ongoing today. Throughout this period, the nation grappled with the political, social, and economic re-integration of the Southern states. The United States underwent an economic transformation that involved a developing industrial economy, the expansion of big business, the growth of large-scale agriculture, and the rise of national labor unions and industrial conflict. Technological change and inventions spurred growth of industry primarily in the northern cities bringing great fortunes to a few and raising the standard of living for millions of Americans. In addition, Westward expansion not only changed the economic structure of the nation, but also demographic patterns and social structures. The expansion of the nation and industry brought forth a desire to find new sources of cheap labor furthering unresolved social and political tensions. 

The growth of the United States on the global stage was a result of innovation as well as the exploration and acquisition of new markets and territories. Global and American trade policies increased profits and opportunities. At the same time, increased power abroad negatively affected many regions. Eventual intervention in World War I ensured America’s role as a world power for the remainder of the century. The crisis of war and involvement in foreign policies caused Americans to refocus their efforts on internal improvements and personal wealth while arts and innovation of the era demonstrated the desire for “American normalcy”. Additionally, “progressive” action, legislation, and new amendments to the Constitution radically transformed the relationship between Americans and their government. 

The roaring twenties ended with the collapse of the American economy. The Great Depression that followed was marked by a stock market crash, and paved the way for greater government involvement in many social and economic institutions throughout the nation. The effectiveness of the policies passed to decrease the severity of the depression are still debated today. As a result of the depression, the nation experienced a second great migration westward by many suffering from unemployment and environmental factors. This migration, once again, changed the demography of the nation, resulting in lasting political and economic changes. America’s involvement in World War II established America as the economic and political powerhouse of the second half of the twentieth century while at the same time reshaping American society. 

Following World War II, the United States emerged as a military, political, and economic super power. These great shifts taking place changed the nation, but also challenged many norms of the previous half-century. American involvement in foreign conflicts to contain communism brought great turmoil both home and abroad. Civic activism challenged previous held beliefs, and paved the way for legal and social changes. 

During the last decade of the 20th century and the beginning of the 21st century, the United States became the world's primary superpower. Possessing the world's most productive economy and powerful military, America dominates global trade and banking. The innovation and globalization of technology, entertainment, and business proved to be both a challenge and an opportunity for the nation. Although contemporary Americans experience terrorism and economic challenges, this period also demonstrates resilience and shows the continued need for American leadership in global events