Why did many Americans favor expansion over isolationism?

Many Americans favored expansion over isolationism in the late 19th and early 20th centuries due to a belief in Manifest Destiny, the idea that the U.S. was destined to expand its territory and influence. Economic motivations, such as the desire for new markets and resources, also played a significant role, as industrialization heightened the need for raw materials and new consumer bases. Additionally, national pride and the belief in spreading democracy and civilization further fueled the push for expansion. This mindset contributed to a more interventionist foreign policy, as seen in events like the Spanish-American War and the annexation of territories.