Final answer:
The theme of the excerpt is America's history of international involvement, highlighting the United States' participation in various conflicts to defend its interests but without facing a major threat to its safety or independence before World War I.
Step-by-step explanation:
The theme of the provided excerpt refers to America's history of international involvement. The passage outlines that while the United States experienced skirmishes and wars with European nations and undertook military actions to defend American rights and principles of peaceful commerce, it was not until World War I that a significant threat challenged the nation's safety or independence. The context of the excerpt, which discusses America's previous wars and international actions alludes to active engagement yet maintains the position that prior to 1914, the US did not face challenges to its sovereignty on the same scale as World War I presented.