Concerning the question of how Southern California churches responded to Nazism and the Holocaust, we should consider the life and work of the Rev. Louis Bauman (1875-1950), who was the pastor of the First Brethren Church of Long Beach, CA from 1913 to 1947.

Rev. Bauman was an influential teacher, speaker, and writer among evangelical Protestants both in Southern California and nationwide. In addition to his work as leader of his own congregation, Bauman was closely associated with the Bible Institute of Los Angeles (today known as Biola University and situated in La Mirada), and was a founder of the Grace Theological Seminary. He wrote for national Christian publications such as The Brethren Missionary Herald, The Brethren Evangelist, and the Sunday School Times, as well as the Bible Institute's monthly magazine, The King's Business.

Bauman's writings focused on trying to demonstrate that various contemporary events constituted fulfillment of biblical prophecies.  Believing that a mass Jewish return to the Holy Land is a necessary part of the messianic process, Bauman saw the Nazi persecution of European Jewry as part of the Divine plan. His intention was not to justify the Nazis' behavior in any way, but to place it in the context of evangelical Protestant theology. 

For our purposes, his writings are important because he made large audiences of church-goers aware of what was happening to the Jews. (In 1933, a Missouri Lutheran periodical, The Concordia Theological Monthly, even criticized some of Bauman's articles for allegedly exaggerating the mistreatment of German Jewry.)  Consider, for example, this excerpt from his article in the May 1934 issue of The King's Business:

Once, not so long ago, Germany was regarded as the most cultured nation on earth. One's education was not complete unless it was climaxed in Germany. But, lo!  How are the mighty fallen! Germany seems to have disposed of all the cerebrum stuff she once possessed--shipped it to Palestine!  And what can be expected from the cerebrum she may have left! A change like this--an insane anti-Semitic outburst in that which was tooted [sic] to be man's most advanced culture--in light of the clear word of prophecy--how tremendously significant!  After studying the situation on the ground the editor of the Catholic 'Commonweal' exclaims:  'A persecution of the Jews, which in its extent probably surpasses any recorded instance of persecution in Jewish history!' >>

Another good example of Rev. Bauman's writings on these subjects can be found in the January 1940 issue of The King's Business:

Remember that the expression, "Jews in Germany," now means not only those in the Germany of a year ago, but the millions that a year ago were in Austria, Czechoslovakia, and Poland. The slow tortured-to-death methods now being used by the Nazi government may not seem so bloody, but are infinitely more cruel than the quick death by the sword.  Antiochus Epiphanes was far more kind than Adolph Hitler.

I should note that Rev. Bauman's articles sometimes contained statements repeating classic anti-Semitic prejudices, especially references to Jews spreading Communism. At the same time, however, one should consider a signed editorial Bauman wrote  for The Brethren Missionary Herald on July 3, 1943, in which he declared: "Now, if there is any such thing as a 'Jewish world coalition' will someone please tell us where its headquarters are? Who is its head?  Wherein has it power?  Millions of agonizing, dying Jews would like to know where they can go for a bit of help."

Overall, Rev. Bauman's articles stand out for two reasons: first, because, on balance, he was one of the few prominent Christian theologians who sought to publicize the plight of the Jews; second, because his writings demonstrate that substantial information about the persecution of the Jews was available to church-goers, even if they generally chose not to act on it.