In the first half of the 20th century, American Jews participated in what can be called the first fully integrated cultural movement in the history of the United States. That movement was jazz music, the beginning of nationwide pop and an artistic playing field that invited people from all walks of life to join in. Together with other American minorities, Jewish musicians contributed to the most influential genre of music in history and the culture it helped create.
Like so much of American society in the early 1900's, music was mostly segregated. White musicians only played with other white musicians, likewise with musicians from black, Irish and other ethnic minority communities. But there was something about jazz that allowed people to overcome that social barrier. As the popular mythology goes, jazz has been depicted as the controversial music of its time, which was true to an extent. Jazz didn't receive nearly as much public animosity as its successors in rock and other pop styles. It's less likely that the wild, youthful nature of jazz or the seedy corners of its subculture drew in such a variety of people as it is that the sheer difficulty of playing jazz music required bands to pull from several different communities. Jazz arrangements require exceptional talent to play properly and there's more than a little uncommon intuition involved with the improvisation and embellishment that are hallmarks of the style. If a jazz band limited itself to musicians based solely on ethnicity, it would miss out on the extraordinary performers from other parts of town.
Though the multicultural jazz bands of the 1930's and 40's were the results of rare talent as much as a general sense of progressive politics, that doesn't mean the integrated bands of Benny Goodman and Stan Getz, as well as the work of contemporary composers like Irvin Berlin, weren't still very important to the growing social change of the era. It's not enough that the ethnically different musicians played together. The real power came in their willingness to perform together in public. The smoky clubs and recording studios of WWII era America were as instrumental in forming the modern civil rights movement as the protests and charismatic leaders of the 1960's. The jazz scene was populated by black musicians who moved north away from Jim Crow laws and Jews who had to change their names just to be accepted as more than second-class citizens. The mutual desire for change, for respect, brought people from oppressed minorities together to make a positive contribution to society.