Historian and newsletter author Heather Cox Richardson is widely assessed by media watchdog groups and critics as having a center-left or progressive lean, though opinions on her neutrality vary depending on the observer's own political perspective.

Media Watchdog Ratings

• Ad Fontes Media: Rates her Substack newsletter, Letters from an American, with a "Strong Left" bias score and a mixed-to-high reliability score, noting that it contains a heavy amount of analysis and opinion.
• Media Bias/Fact Check: Gives her publication a "Left bias" rating paired with a "High" rating for factual reporting, finding no failed fact checks.

Criticisms and Perspectives

• Left-Leaning / Progressive Framing: Critics from conservative and center-right publications—such as the Claremont Review of Books and The Free Press—argue that her writing functions as a partisan narrative, framing contemporary politics through a progressive lens, selectively presenting historical events, and casting modern Republicans or Donald Trump as an existential threat to democracy.
• Left / Socialist Critiques: Some leftist and socialist critics argue that her work relies too heavily on an idealized view of mainstream American liberalism and figures like Abraham Lincoln, while glossing over systemic or class-based failures inherent to the broader U.S. political system.
• Supporters' View: Admirers and readers often view her as a stabilizing, well-researched guide who uses primary historical sources to contextualize chaotic daily news cycles rather than practicing partisan spin.
Richardson has described her personal political background as historically aligned with a Lincoln-era Republican outlook, while frequently arguing that the modern Republican party has drifted far from its historical roots.