"In this longitudinal analysis, Republican-led states had fewer per capita COVID-19 cases, deaths, and positive tests early in the pandemic, but these trends reversed in early May (positive tests), June (cases), and July (deaths). Testing rates were similar until September, when Republican states fell behind Democratic states. The early trends could be explained by high COVID-19 cases and deaths among Democratic-led states that are home to initial ports of entry for the virus in early 2020. However, the subsequent reversal in trends, particularly with respect to testing, may reflect policy differences that could have facilitated the spread of the virus. Adolph et al. found that Republican governors were slower to adopt both stay-at-home orders and mandates to wear face masks. Other studies have shown that Democratic governors were more likely to issue stay-at-home orders with longer durations. Moreover, decisions by Republican governors in spring 2020 to retract policies, such as the lifting of stay-at-home orders on April 28 in Georgia, may have contributed to increased cases and deaths. Democratic states also had lower test positivity rates from May 30 through December 15, suggesting more rigorous containment strategies in response to the pandemic. Thus, governors’ political affiliation might function as an upstream progenitor of multifaceted policies that, in unison, impact the spread of the virus. Although there were exceptions in states such as Maryland and Massachusetts, Republican governors were generally less likely to enact policies aligned with public health social distancing recommendations."