Years ago, Rabbi Byron Sherwin z”l taught a class titled “What is Judaism?” He referenced his newly published book, Finding Faith in Meaning. He mentioned the extent of the challenges faced by those Conversos who had escaped into areas where they could openly practice Judaism. He stated:
“Despite their sincere desire to return to the Jewish faith and the Jewish fold, [who had fled the Iberian Peninsula] had many obstacles to overcome. Though they had left Spain and Portugal behind, though many had divested themselves of Christianity, though many had exchanged their Spanish names for Hebrew names, and though some had accepted harsh penances as the price of “return,” most “new Jews” retained the culture and the language of Spain and Portugal. They not only remained influenced by Christian doctrines but also intended to understand the nature of Jewish identity and Judaism through the prism of Spanish-Catholic teachings. As one of them put it, ‘It is truly difficult to desert a religion which one has known from the cradle.’ ”
What was striking is that Rabbi Sherwin continued in his lecture by stating that American Jews were effectively Conversos. That is, the American Jewish experience is reflective of what Rabbi Sherwin referred to as the Protestantization of Judaism. Jews are living in two worlds. American Jews of all backgrounds, Reform, Conservative, and even Orthodox have been heavily influenced by Christian patterns of thought even as they have striven to live Jewish lives.
The impact is sometimes indirect while more explicit in others. The comparison to Conversos lies in the fact that many Conversos struggled to keep a sliver of Judaism alive but it was often impossible for them not be influenced by the dominant Christian environment. The American Jewish experience, albeit, is a different once in the sense that American Jews have been subject to a largely receptive country where Jews have prospered openly as Jews. America has been wonderful for Jews. The question Rabbi Sherwin posed was whether America had been wonderful for Judaism.
Its a challenging question and the study of the Converso experience is a helpful exercise in understanding and reflecting on other Jewish issues.
 Byron Sherwin, Finding Faith in Meaning: A Theology of Judaism, (Oxford: Oxford University Press, 2009), p. 6.