This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this recordData availability statement: Data replication sets are available at https://dataverse.harvard.ed/atavers/JPolSStudies of the American public demonstrate that partisans often diverge not only on questions of opinion but also on matters of fact. However, little is known about partisan divergence in factual beliefs among the government officials who make real policy decisions, or how it compares to belief polarization among the public. This letter describes the first systematic comparison of factual belief polarization between the public and government officials, which we conducted using a paired survey approach. Th...