Skip to main content

The Politics of Policy: The Initial Mass Political Effects of Medicaid Expansion in the States


Whether public policy affects electoral politics is an enduring question with an elusive answer. We identify the impact of the highly contested Patient Protection and Affordable Care Act (ACA) of 2010 by exploiting cross-state variation created by the 2012 Supreme Court decision in National Federation of Independent Business v. Sebelius. We compare changes in registration and turnout following the expansion of Medicaid in January of 2014 to show that counties in expansion states experience higher political participation compared to similar counties in nonexpansion states. Importantly, the increases we identify are concentrated in counties with the largest percentage of eligible beneficiaries. The effect on voter registration persists through the 2016 election, but an impact on voter turnout is only evident in 2014. Despite the partisan politics surrounding the ACA–a political environment that differs markedly from social programs producing policy feedbacks in the past—our evidence is broadly consistent with claims that social policy programs can produce some political impacts, at least in the short-term.

Corresponding author
Joshua D. Clinton is the Abby and Jon Winkelried Chair and Professor of Political Science, Vanderbilt University, PMB 505, 230 Appleton Place, Nashville, TN 37203-5721 (
Michael W. Sances is an Assistant Professor of Political Science, University of Memphis, 421 Clement Hall, Memphis, TN 38152 (
Hide All

Helpful reactions were provided by seminar participants at Vanderbilt, UCLA, Princeton University, Yale University, and the University of British Columbia. This article has been supported in part by Award No. 94-16-06 from the Russell Sage Foundation. All opinions and errors are our own.

Hide All
Angrist Joshua D., and Pischke Jrn-Steffen. 2009. Mostly Harmless Econometrics: An Empiricist’s Companion. Princeton, NJ: Princeton University Press.
Arnold R. Douglas. 1990. The Logic of Congressional Action. New Haven, CT: Yale University Press.
Baicker Katherine, Taubman Sarah L., Allen Heidi L., Bernstein Mira, Gruber Jonathan, Newhouse Joseph, Schneider Eric C., Wright Bill J., Zaslavsky Alan M., and Finkelstein Amy N.. 2013. “The Oregon Experiment: Effects of Medicaid on Clinical Outcomes.” The New England Journal of Medicine 368 (18): 1713–22.
Balz Dan. 2010. “Introduction.” In Landmark: The Inside Story of America’s New Health-Care Law-The Affordable Care Act-and What it Means for Us All. Philadelphia: PublicAffairs.
Bartels Larry. 2008. Unequal Democracy: The Political Economy of the Gilded Age. Princeton, NJ: Princeton University Press.
Béland Daniel, Rocco Philip, and Waddan Alex. 2016. Obamacare Wars: Federalism, State Politics, and the Affordable Care Act. Lawrence, KS: University of Kansas Press.
Bendor Jonathan. 2010. Bounded Rationality and Politics. Berkeley, CA: University of California Press.
Bendz Anna. 2015. “Paying Attention to Politics: Public Responsiveness and Welfare Policy Change.” Policy Studies Journal 43 (3): 309–32.
Blais Andre. 2000. To Vote or Not to Vote? The Merits and Limits of Rational Choice Theory. University of Pittsburgh Press.
Brill Steven. 2015. America’s Bitter Pill: Money, Political, Backroom Deals, and the Fight to Fix our Broken Healthcare System. New York, NY: Random House.
Brooks Tricia, Touscher Joe, Artiga Samantha, Stephens Jessica, and Gross Alexandra. 2015. “Modern Era Medicaid: Findings from a 50-State Survey of Eligibility, Enrollment, Renewal, and Cost-Sharing Policies in Medicaid and CHIP as of January 2015.” Kaiser Commission on Medicaid and the Insured. Accessed September 8, 2016.
Burden Barry C., Fletcher Jason M., Herd Pamela, Moynihan Donald P., and Jones Bradley M.. 2017. “How Different Forms of Health Matter to Political Participation.” The Journal of Politics 79 (1): 166–78.
Cameron Colin A., Gelbach Jonah B., and Miller Douglas L.. 2008. “Bootstrap-Based Improvements for Inference with Clustered Errors.” The Review of Economics and Statistics 90 (3): 414–27.
Campbell Andrea Louise. 2003. How Policies Make Citizens: Senior Political Activism and the American Welfare State. Princeton, NJ: Princeton University Press.
Campbell Andrea Louise. 2012. “Policy Makes Mass Politics.Annual Review of Political Science 15: 333–51.
Card David, and Krueger Alan B.. 1994. “Minimum Wages and Employment: A Case Study of the New Jersey and Pennsylvania Fast Food Industries.” American Economic Review 84 (4): 772–93.
Dell Melissa. 2010. “The Persistent Effects of Peru’s Mining Mita .” Econometrica 78 (6): 1863–903.
Derthick Martha. 1979. Policymaking for Social Security. Washington, DC: The Brookings Institution.
Dube Arindrajit, Lester T. William, and Reich Michael. 2010. “Minimum Wage Effects Across State Borders: Estimates Using Contiguous Counties.” Review of Economics and Statistics 92 (4): 945–64.
Eichelberger Erika. 2014. “Obamacare Could Have Turned Millions of Uninsured Americans into Voters.” Mother Jones, November 4. Accessed August 5, 2015.
Finkelstein Amy, Taubman Sarah, Wright Bill, Bernstein Mira, Gruber Jonathan, Newhouse Joseph P., Allen Heidi, and Baicker Katherine. 2012. “The Oregon Health Insurance Experiment: Evidence from the First Year.” Quarterly Journal of Economics 127 (3): 1057–106.
Gilens Martin. 2012. Affluence and Influence: Economic Inequality and Political Power in America. Princeton, NJ: Princeton University Press.
Green Donald P., Ha Shang E., Bullock John G.. 2010. “Enough already about ‘black box’ experiments: Studying mediation is more difficult than most scholars suppose.” The Annals of the American Academy of Political and Social Science 628 (1): 200–8.
Hacker Jacob S., and Pierson Paul. 2010. “Winner-Take-All Politics: Public Policy, Political Organization, and the Precipitous Rise of Top Incomes in the United States.” Political Sociology 38: 152204.
Hagan Elizabeth. 2016. “ACA Assisters Can Help Consumers Register to Vote.” The Upshot, July 4. Accessed May 22, 2017.
Haselswerdt Jake. 2017. “Expanding Medicaid, Expanding the Electorate: The Affordable Care Act’s Short-Term Impact on Political Participation.” The Journal of Health Politics, Policy and Law 42 (4): 667–95.
Henderson Michael, and Hillygus D. Sunshine. 2011. “The Dynamics of Health Care Opinion, 2008-2010: Partisanship, Self-Interest, and Racial Resentment.” Journal of Health Politics, Policy and Law 36 (6): 945–60.
Highton Benjamin, and Wolfinger Raymond E.. 2001. “The Political Implications of Higher Turnout.” British Journal of Political Science 31 (1): 179223.
Holmes Thomas J. 1998. “The Effects of State Policies on the Location of Manufacturing: Evidence from State Borders.” Journal of Political Economy 106 (4): 667705.
Imai Kosuke, Keele Luke, Tingley Dustin, and Yamamoto Teppei. 2011. “Unpacking the Black Box of Causality: Learning About Causal Mechanisms from Experimental and Observational Studies.” American Political Science Review 105 (4): 765–89.
Keele Luke, Lorch Scott, Passarella Molly, Small Dylan, and Titiunik Rocio. 2017. “An Overview of Geographically Discontinuous Treatment Assignments With An Application to Children’s Health Insurance.” In Regression Discontinuity Designs: Theory and Applications, Advances in Econometrics 38: 147–94.
Keele Luke J., and Titiunik Rocio. 2015. “Geographic Boundaries as Regression Discontinuities.” Political Analysis 23 (1): 127–55.
Kliff Sarah. 2016. “Why Obamacare enrollees voted for Trump.” Vox. Accessed December 15, 2016.
Kriner Douglas L., and Reeves Andrew. 2014. “Responsive Partisanship: Public Support for the Clinton and Obama Health Care Plans.” Journal of Health Politics, Policy and Law 39 (4): 717–49.
Lee David S., and Lemieux Thomas. 2010. “Regression Discontinuity Designs in Economics.Journal of Economic Literature 48: 281355.
Leighley Jan E., and Nagler Jonathan. 2014. Who Votes Now? Demographics, Issues, Inequality And Turnout In The United States. Princeton, NJ: Princeton University Press.
Leip David. 2017. “Dave Leip’s Atlas of US Presidential Elections.” Accessed May 30, 2017.
Lerman Amy E., and McCabe Katherien T.. 2017. “Personal Experience and Public Opinion: A Theory and Test of Conditional Policy Feedback,” Journal of Politics, forthcoming.
Lerman Amy E., Sadin Meredith L., and Trachtman Samuel. 2017. “Policy Uptake as Political Behavior: Evidence from the Affordable Care Act.American Political Science Review 111 (4): 755–70.
McCabe Katherine T. 2016. “Attitude Responsiveness and Partisan Bias: Direct Experience with the Affordable Care Act.” Political Behavior, forthcoming.
McCrary Justin. 2008. “Manipulation of the Running Variable in the Regression Discontinuity Design: A Density Test.” Journal of Econometrics 142 (2): 698714.
Meredith Marc, and Morse Michael. 2015. “The Politics of the Restoration of Ex-Felon Voting Rights: The Case of Iowa.” Quarterly Journal of Political Science 10 (1): 41100.
Mettler Suzanne. 2002. “Bringing the State Back in to Civic Engagement: Policy Feedback Effects of the G.I. Bill for World War II Veterans.” The American Political Science Review 96 (2): 351–65.
Mettler Suzanne. 2005. Soldiers to Citizens: The G.I. Bill and the Making of the Greatest Generation. New York, NY: Oxford University Press.
Mettler Suzanne, and Soss Joe. 2004. “The Consequences of Public Policy for Democratic Citizenship: Bridging Policy Studies and Mass Politics.” Perspectives on Politics 2 (1): 5573.
Mettler Suzanne, and Stonecash Jeffrey M.. 2008. “Government Program Usage and Political Voice.” Social Science Quarterly 89 (2): 273–93.
Michener Jamila. 2015. “Medicaid, Federalism, and Political Participation.” Working paper, Department of Government, Cornell University.
Newkirk Margaret. 2017. “Why Kentucky Couldn’t Kill Obamacare: A Lesson for Congress,” Bloomberg, January 23. Accessed May 24, 2017.
Novack Sophie. 2013. “Obamacare May Be More Political Than You Think.” National Journal, October 14. Accessed June 16, 2015.
Onek Joe. 2015. “How Obamacare curtails voter registration.” The Hill, October 30. Accessed September 4, 2017.
Pacheco Julianna, and Fletcher Jason. 2015. “Incorporating Health into Studies of Political Behavior: Evidence for Turnout and Partisanship.” Political Research Quarterly 68 (1): 104–16.
Patashnik Eric M. 2014. Reforms at Risk: What Happens After Major Policy Changes Are Enacted. Princeton, NJ: Princeton University Press.
Patashnik Eric, and Zelizer Julian E.. 2013. “The Struggle to Remake Politics: Liberal Reform and the Limits of Policy Feedback in the Contemporary American State.” Perspectives on Politics 11 (4): 1071–87.
Pierson Paul. 1993. “When Effect Becomes Cause: Policy Feedback and Political Change.” World Politics 45 (4): 595628.
Pierson Paul. 1992. “Policy Feedbacks and Political Change: Contrasting Reagan and Thatcher’s Pension Reform Initiatives.” Studies in American Political Development 6 (2): 359–90.
Powell G. Bingham. 1986. “American Voter Turnout in Comparative Perspective.” American Political Science Review 80 (1): 1743.
Roth Zachary. 2014. “Obamacare Helping Millions Register to Vote.” MSNBC, March 3. Accessed August 5, 2017.
Schattschneider E. E. 1935. Politics, Pressures, and the Tariff. New York, NY: Prentice-Hall.
Schlozman Kay Lehman, Verba Sidney, and Brady Henry E.. 2012. The Unheavenly Chorus: Unequal Political Voice and the Broken Promise of American Democracy. Princeton, NJ: Princeton University Press.
Schneider Anne, and Ingram Helen. 1993. “Social Construction of Target Populations: Implications for Politics and Policy.” American Political Science Review 87 (2): 334–47.
Schwartz Aaron L., and Sommers Benjamin D.. 2014. “Moving for Medicaid? Recent Eligibility Expansions Did Not Induce Migration From Other States.” Health Affairs 33 (1): 8894.
Sharp Elaine B. 2012. Does Local Government Matter? How Urban Policies Shape Civic Engagement. Minneapolis, MN: University of Minnesota Press.
Skocpol Theda. 1991. “Targeting Within Universalism: Politically Viable Policies to Combat Poverty in the United States.” In The Urban Underclass, eds. Jencks Christopher and Peterson Paul E.. Washington, DC: Brookings Institution.
Sommers Benjamin D., Baicker Katherine, and Epstein Arnold M.. 2012. “Mortality and Access to Care Among Adults After State Medicaid Expansions.” New England Journal of Medicine 367 (11): 1025–034.
Soroka Stuart Neil, and Wlezien Christopher. 2010. Degrees Of Democracy: Politics, Public Opinion, and Policy. New York: Cambridge University Press.
Soss Joe. 1999. “Lessons of Welfare: Policy Design, Political Learning, and Political Action.” American Political Science Review 93 (2): 363–80.
Soss Joe. 2002. Unwanted Claims: The Politics of Participation in the US Welfare System. Ann Arbor, MI: University of Michigan Press.
United States Census Bureau. 2017. “Model-based Small Area Health Insurance Estimates (SAHIE) for Counties and States.” Accessed May 30, 2017.
Weaver Vesla M., and Lerman Amy E.. 2010. “Political Consequences of the Carceral State.” American Political Science Review 104 (4): 817–33.
Wilson William Julius. 1987. The Truly Disadvantaged: The Inner City, the Underclass, and Public Policy. Chicago: University of Chicago Press.
Wolfinger Raymond E., and Rosenstone Steven. 1980. Who Votes? New Haven, CT: Yale University Press.
Recommend this journal

Email your librarian or administrator to recommend adding this journal to your organisation's collection.

American Political Science Review
  • ISSN: 0003-0554
  • EISSN: 1537-5943
  • URL: /core/journals/american-political-science-review
Please enter your name
Please enter a valid email address
Who would you like to send this to? *
Type Description Title
Supplementary materials

Clinton and Sances Dataset

Supplementary materials

Clinton and Sances supplementary material 1

 PDF (3.3 MB)
3.3 MB


Altmetric attention score

Full text views

Total number of HTML views: 60
Total number of PDF views: 362 *
Loading metrics...

Abstract views

Total abstract views: 230551 *
Loading metrics...

* Views captured on Cambridge Core between 2nd November 2017 - 22nd February 2018. This data will be updated every 24 hours.