32Objectives: To explore whether state-level political-sentiment is associated with gains in 33 insurance post Affordable Care Act (ACA). This is especially relevant given the lawsuit brought 34 by several Republican-leaning states against the ACA, and the ruling of one Texas federal judge 35 that the ACA is unconstitutional, which potentially jeopardizes ACA's future. 36 Methods: Multivariate linear-probability models are estimated using data from the Behavioral 37 Risk Factor Surveillance Systems for 2011-2017. The outcome is self-reported insurance status. 38 States are placed in quartiles based on votes for President Obama in 2008 and 2012 elections. 39 Starting 2014, ACA health exchanges became active and several states expanded Medicaid, so 40 2014 onwards is considered as the 'post-ACA' period. Models are estimated for all adults under 41 65-years and for young adults under 35-years. All models control extensively for respondent socio-42 economic-demographic characteristics and state characteristics.43 Results: In the pre-ACA baseline period, respondents in states with higher Anti-Obama-voting 44 (AOV) were less likely to have insurance. For example, residents in highest AOV-quartile states 45 were 8.0-percentage-points less likely (p<0.001) to have insurance than those in the lowest AOV-46 quartile states. Post-ACA, fewer high AOV-quartile states expanded Medicaid, and overall 47 48 Medicaid-expansion, residents in higher AOV states saw higher insurance gains. For example, all 49 adults had 2.8-percentage points higher likelihood (p<0.01) and young adults had 4.9-percentage 50 point higher likelihood (p<0.01) of getting insurance in the highest AOV-quartile states compared 51 to the lowest AOV quartile states. Minorities and those with chronic-conditions had larger 52 insurance gains across the country post-ACA, but the extent of these gains did not differ by state 53 AOV levels. 3 54 Conclusions: State AOV and insurance gains from ACA appear to be incongruent. Policymakers 55 and stakeholders should be aware that non-Medicaid residents of higher-AOV states might 56 potentially lose the most if ACA is revoked. 58 The Patient Protection and Affordable Care Act (hereafter ACA) very substantially 59 changed the health insurance landscape in the United States, and scientific research indicates that 60 although there were significant increases in rates of health insurance coverage in the U.S. after 61 its passage, yet opinions about the ACA remain deeply divided along political lines [1-6]. The 62Kaiser Health Tracking Poll [7] shows that overall unfavorable ratings of ACA dropped from a 63 high of 53% in July 2014 to 40% in November 2018. However, among those who identify as 64 Republicans, approximately 75% continue to view it unfavorably, while less than 20% of those 65 who identify as Democrats and about 45% of those who identify as Independents do so. The 66 ACA's future also remains uncertain under the current administration. One key provision, the 67 'individual mandate' that requires indiv...