Presidential candidate endorsements by scientific journals decrease trust in science especially for moderate and conservative Americans

Before the 2020 and 2024 US Presidential elections, several scientific journals publicly endorsed the Democratic candidates or opposed the Republican candidate. We conducted three highly-powered, pre-registered online experiments ( N = 6,281) to examine how these endorsements affected trust in science. Results revealed significant declines in trust in science, driven primarily by moderate and conservative Americans. Drawing upon on the theoretical perspective that trust in science is not monolithic, but rather composed of distinct dimensions, we examined and observed effects across a range of trust-related domains, including perceptions of scientific integrity (impartiality), competence (ability), benevolence, and generalized trust in scientific institutions. These findings highlight how motivated reasoning can amplify existing skepticism when individuals who already perceive science as aligned with opposing political ideologies read political endorsements from within the scientific community. Amidst increasing science-skepticism and politicization, journals must consider the unintended consequences of political messaging on public perceptions of science.