In the early 1950s, Oppenheimer's opposition to building the hydrogen bomb and his past association with leftists led to a hearing regarding his security clearance. Although the committee found that he was a “loyal citizen,” his security clearance was not restored, and he was barred from government research. Oppenheimer's chief opponent in the scientific community at this time was Edward Teller.
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.