Al Jolson playing The Jazz Singer, photo source: lifeinla.com
This is about following your dreams as an American umbrella religion for all its sons. But don't watch The Jazz Singer (1927) for its propaganda* - it has enormous artistic and innovative value (and it gathers timeless music.) In this clip, the jazz singer is fulfilling his dying father's wish, being a cantor for The Day of Atonement.
|photo source eldridgestreet.org|
The Jazz Singer is an example of creating a US identity through domestic policy of containing otherness (though Jewish people were not perceived as un-American, they were still immigrants) concomitantly with transmitting a political message outside: the immigrants are Americanized, accepted, while the second generation is voluntarily renouncing their inherited obligations (cantor) and traditions (he is having a relationship with a non-Jewish woman.)
The signification is that people, not matter where they come from, are firstly Americans. Being white doesn’t cover the character’s Jewish fingerprint, and Judaism is not a race; so, "to become American...", to paraphrase Seth Fein, "...he has to be a black Jazz singer." Using stereotypes for the country, jazz and white, not as color per se, but white in opposition to black, the singer is distancing himself from his birth-inherited distinctive Jewishness and is embracing an American identity by playing with race and ethnic identity.