Final answer:
The U.S. Army earned the most streamers during World War II, with highly decorated units such as the 100th Infantry Battalion and the 442nd Regimental Combat Team contributing to this count significantly. The expansion of the Army and Navy and a strategy based on attrition underline the vast scale of the Army's participation.
Step-by-step explanation:
The U.S. Army earned the most streamers during World War II. This period of conflict saw immense mobilization and the creation of segregated units such as the 100th Infantry Battalion and the 442nd Regimental Combat Team, which were among some of the best infantrymen in the U.S. Army and known as the most decorated unit in US military history for their size and length of service. The Army's composition and strategy during this time reflect the intense nationalism and sense of moral crusade that characterized American participation in the wars, something that was not only reflected in military achievements but also in popular culture and political ideology.
Congress was instrumental in the expansion of the Army and Navy, ensuring supplies and financing, while also maintaining an independent U.S. command in Europe as insisted by General Pershing. The sacrifices made by soldiers were immense, as war strategists adopted a war of attrition designed to outlast the enemy at great human cost. Through this lens of massive engagement and significant contribution, it's clear that World War II stands out in terms of streamers and the sheer scale of military involvement.