During the 1970s, passionate and sometimes violent political disagreements wracked the scientific community in the United States. Insurgent movements on campuses called for an end to classified research and university defense contracting. New Left factions linked deep structural critiques of American science to damning analyses of imperialism and global inequity, challenging notions of neutrality and demanding sweeping changes at all research levels. Yet at the very moment when critics were launching powerful new intellectual attacks on science, women were entering STEM fields in record numbers, where they confronted sexism within their professions and a maelstrom of epistemological battles over essentialism, objectivity, and the social construction of scientific facts. Overlapping contingents of antiwar activists, feminists, and citizen scientists argued over two central questions: What counts as science? And who counts as a scientist? These interlocking disputes over the practice and meaning of science in the 1970s shaped scientific discourse and activism in the late Cold War and have had far-reaching implications for popular attitudes and policies in the twenty-first century.