American History often refers back to previously discussed topics to draw comparisons between seemingly distinct and unrelated time periods. By doing this, it helps highlight important trends and common themes. The most visible trends include the cycle of the American economy, the rise and fall of conservatism and progressivism, and the push and pull of American foreign policy between isolationism and interventionism. American History presents all these trends as interrelated.

Throughout US history, the economy has repeatedly—and in a surprisingly consistent pattern—undergone periods of boom and bust. Economic cycles often relate to US involvement in wars, particularly in the period between and after the two World Wars. During the 1920s and 1950s, after World War I and World War II respectively, the US entered periods of great economic growth that closely accompanied developments in American technology. Shortly after these booms came times of economic decline: the Great Depression of the 1930s and the recession of the 1970s. Although the exact causes of these declines differed, both followed relatively unchecked growth during the postwar booms. These trends are not confined to the 20th century: After the Civil War, the North saw a period of significant industrial growth followed by an economic low period during the 1890s.