What does blue on the U.S. flag represent?

The blue on the U.S. flag symbolizes vigilance and loyalty. In the context of the flag's design, the colors were selected with specific meanings in mind as articulated by Charles Thomson, the designer of the Great Seal of the United States. He described the color blue as representing "vigilance, perseverance, and justice." However, in the context of the flag, the emphasis is often placed on vigilance and loyalty, reflecting the ideals that the nation values in its citizens and leadership. These traits are critical in the context of national service and the responsibilities of citizenship, aligning with the foundational principles of the United States. Thus, blue not only embodies the importance of steadfastness but also a commitment to the ideals and duties of the country.