In the 1970s, he welcomed the insights of the Theology of Liberation that came from Latin America and other societies. He also became interested in the work of Karl Mannheim and developed a program of ideology critique that he hoped would eliminate the ideological or prejudicial elements in religion.
In the 1980s and 1990s, Baum continued his study into ideology critique by integrating the work of the Frankfurt School of Critical Theory. He connected the Frankfurt School's concept of "the end of innocent critique" with Liberation theology's "preferential option for the poor".