The Union flag, known as the Stars and Stripes, symbolized unity and patriotism

https://kylerstiu890.oakridgedigest.com/posts/collecting-civil-war-flags-a-guide-for-enthusiasts

The Union flag, which is called the Stars and Stripes, symbolized cohesion and patriotism, featuring thirteen stripes and a discipline of blue with stars that represented every state in the union.