Complex sentence: Jacoby has spoken about the important role secularism played in the development of political and social events in the history of the United States, and she has argued that this fact is often written out of American history by the religious right.
Split into simpler sentences: Jacoby has spoken about the important role secularism played in the development of political and social events in the history of the United States. She has argued that this is often written out of American history by the religious right.