As we explain in the text, there is a reason why this particular song triggers such an emotional reaction:
The song “God Bless America” lay at the crossroads of civil religion, war, and voluntary service. Irving Berlin wrote it in 1918, and it became more popular after the Second World War drew near. People sang it at public meetings, and there was an attempt to make it the national anthem. During bad times, people took heart from its plea to God to stand beside and guide the United States. In 1940, Berlin set up the God Bless America Foundation, which directed royalties to the Boy and Girl Scouts of America. According to a foundation trustee, “the completely nonsectarian work of the Boy Scouts and Girl Scouts was calculated to best promote unity of mind and patriotism, two sentiments that are inherent in the song itself.”
Right after the 9/11 attacks, Americans sang it in churches, auditoriums, and on the steps of the Capitol:
The May 2 rendition of the song thus provided an appropriate sense of closure.