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January 3, 2019

Medicaid Expansion Gains Momentum: Postelection Prospects and Potential Implications

Author Affiliations
  • 1Department of Health Policy and Management, Harvard T.H. Chan School of Public Health, Boston, Massachusetts
  • 2Cambridge Health Alliance, Cambridge, Massachusetts
  • 3Department of Medicine, Brigham & Women’s Hospital, Boston, Massachusetts
JAMA. Published online January 3, 2019. doi:10.1001/jama.2018.20484

Health care was rated one of the key issues for voters in the 2018 midterm elections, according to exit polls. The election results set the stage for as many as 500 000 low-income individuals in the United States to gain coverage through new state Medicaid expansions under the Affordable Care Act (ACA). Expansion could occur in 5 additional states: 3 through ballot measures (Idaho, Nebraska, and Utah) and 2 through the election of new governors supportive of expansion (Kansas and Maine). If all 5 states expand Medicaid, this will bring the number of expansion states to 37 (plus Washington, DC), with a potential increase in Medicaid enrollees from approximately 50 million in 2010 prior to enactment of the ACA to a projected 76 million by 2020 (Figure and eFigure in the Supplement). The election also brings some short-term legislative certainty for the ACA, as the new Democratic majority in the House of Representatives will forestall further attempts to repeal the law for at least 2 years. In this Viewpoint, we provide a postelection update on the status of the Medicaid expansion and recent research on the ongoing effects of the law.

Two gubernatorial elections will likely result in new state Medicaid expansions. Maine became the first state to expand Medicaid through a ballot initiative in December 2017, but Republican Gov Paul LePage refused to implement the program, despite court orders to do so. Democrat Janet Mills campaigned on expanding Medicaid, and her election creates a clear path forward for the expansion. Although such projections are inherently imprecise, policy analysts estimate that Medicaid expansion in Maine could cover an additional 56 000-72 000 individuals (eTable in the Supplement). Medicaid expansion is also a strong possibility in Kansas, where newly elected Democrat Laura Kelly is committed to expansion. She will have the likely support of the Republican-controlled legislature, which passed a Medicaid expansion bill in 2017 that was vetoed by then Gov Sam Brownback. Medicaid expansion in Kansas could provide coverage to an additional estimated 129 000-152 000 Kansans. Wisconsin also elected a new governor, Democrat Tony Evers, who has indicated support for expanding Medicaid, although the state’s legislature remains opposed, making an imminent expansion in Wisconsin unlikely.

Ballot initiatives supporting Medicaid expansion were successful in 3 states, although as in Maine, expansions in these states could be blocked by state officials who oppose the change. However, if the initiatives are implemented, Utah is expected to experience the largest Medicaid coverage expansion, with an estimated 100 000-158 000 new beneficiaries. The Utah ballot measure finances the program through an increase in the state sales tax, which is expected to cover the full $77 million projected annual cost to the state of expansion. In Idaho, an estimated 51 000-119 000 individuals are expected to enroll in Medicaid, at a projected annual cost to the state of $39 million to $42 million. In Nebraska, an estimated 68 000-93 000 individuals could enroll, with state expenditure projected to be $36 million to $64 million. The vast majority of expansion costs in all of these states would be borne by the federal government, which pays for 93% of the expansion in 2019 and 90% thereafter, as stipulated in the ACA.

Evidence on Expansion

A growing literature suggests that new Medicaid enrollees in these states will experience benefits in terms of health care access, preventive services, and physical health.1 Affordability of care has also improved considerably under the ACA for Medicaid-eligible adults.2 Newly published research suggests that some of the most significant effects may occur for persons with chronic diseases. One recent study found that nonelderly adults initiating dialysis (who typically do not qualify for Medicare until 4 months after starting dialysis) experienced a 10% relative reduction in mortality after Medicaid expansion, the first published study linking coverage expansion following the ACA with changes in survival.3

State officials opposed to expansion have, for many years, maintained that Medicaid expansion is financially irresponsible for states. However, research indicates that state budgets have been minimally affected by expansion thus far due to generous federal matching rates, and some states have even experienced net savings.4 An analysis of state budgets in expansion states compared with nonexpansion states found that expansion did not result in reductions in state spending for other sectors such as education or transportation.5 Opponents to expansion have also cited the uncertain future of the federal matching funds for expansion, in light of efforts to repeal the ACA. This concern is mitigated for the time being by the new Democratic majority in the House, but of course this is subject to change after the 2020 elections.

Remaining Uncertainty

Despite renewed momentum toward expansion after the election, significant challenges and uncertainty regarding Medicaid remain. In Montana, voters rejected a tobacco tax that would have funded the continuation of the Medicaid expansion in that state, which is set to expire in June 2019. The fate of Montana’s expansion will depend on whether state lawmakers can identify another source of funding. Republican victories in gubernatorial races in Florida and Georgia, where more than 2.2 million people could have become eligible for Medicaid, likely rule out expansion in those states for at least 4 years. Ballot initiatives may become an increasingly attractive option for supporters of expansion in these and other states.

Another recent challenge has arisen for the stability of Medicaid coverage for low-income adults: several states are pursuing new work requirements for Medicaid. Fourteen states have submitted applications to CMS to require nondisabled adults in Medicaid to work or participate in other “community engagement activities” to maintain coverage; 5 states’ applications have been approved thus far. In Arkansas, the first state where work requirements are in effect, more than 8000 people have been disenrolled due to failure to report any work or disability status, and one estimate suggests that coverage losses could reach more than 48 000 adults within a year.6 No information is yet available about the effect of disenrollment on health outcomes for these individuals. In June, 2018, a federal judge barred the work requirement in Kentucky from taking effect, and a similar lawsuit against work requirements in Arkansas is currently pending.

The complexion of US health care coverage has changed substantially since passage of the ACA. According to the US Census Bureau, in 2010 the number of individuals who were uninsured was 50 million, with another 50 million insured through Medicaid (although census numbers typically undercount Medicaid compared with official enrollment statistics), 44 million through Medicare, and 196 million with private insurance; these estimates include some individuals who reported multiple types of insurance (Figure). Projections are quite different for 2020 (assuming the 5 states above expand Medicaid), with the largest increase in Medicaid, and smaller increases in Medicare (due to the aging of the population) and private coverage. The overall uninsured population is projected to be approximately 30 million by 2020. These estimates are adapted from various projections from the Census Bureau and the Congressional Budget Office and are inherently uncertain, but they nonetheless depict the broad changes in the health insurance landscape over the course of this decade.

Distribution of Insurance Coverage for the US Population in 2010 and Projected Coverage for 2020, in Millionsa
Distribution of Insurance Coverage for the US Population in 2010 and Projected Coverage for 2020, in Millionsa

“Private insurance” includes employer-based insurance, individual market insurance, and coverage obtained from the Affordable Care Act Marketplaces. 2020 Estimates are based on the following sources (see eFigure in the Supplement for further assumptions and explanations).

a2010 Coverage from Table C1 in: DeNavas-Walt C, Proctor B, Smith J. Income, Poverty, and Health Insurance Coverage in the United States: 2010. Washington, DC: US Census Bureau; 2011. Estimates for 2020 based on an estimated population of 335 million, from Table 1 in: Colby SL, Ortman JM. Projections of the Size and Composition of the US Population: 2014 to 2060.

bEstimate is a sum of 172 million nonelderly individuals from Table 1 in https://www.cbo.gov/publication/53091, combined with the projected share of elderly adults with private coverage.

cMedicaid estimate comes from adding 500 000 individuals from the projected 2019 expansion states to estimates from: Medicaid—CBO’s April 2018 Baseline. https://www.cbo.gov/system/files?file=2018-06/51301-2018-04-medicaid.pdf.

dMedicare estimate from: Medicare—CBO’s April 2018 Baseline. https://www.cbo.gov/sites/default/files/recurringdata/51302-2018-04-medicare.pdf.

eEstimate is a sum of 5 million nonelderly individuals from Table 1 in https://www.cbo.gov/publication/53091, combined with the projected share of elderly adults with other coverage.

fEstimate comes from subtracting 500 000 individuals based on the projected 2019 expansion states to estimates from: Congressional Budget Office. Federal Subsidies for Health Insurance Coverage for People Under Age 65: 2017 to 2027. https://www.cbo.gov/publication/53091.


In conclusion, the 2018 midterm election will have important effects on health care, most notably by bringing Medicaid expansion under the ACA to several more states. These election results, particularly in the form of ballot initiatives, indicate that Medicaid expansion has popular support that in some cases transcends party lines. Nonetheless, while Medicaid expansion clearly gained significant momentum this November, the future of the program will again be at stake on state and federal ballots in 2020.

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Article Information

Corresponding Author: Benjamin D. Sommers, MD, PhD, Harvard T.H. Chan School of Public Health, 677 Huntington Ave, Room 406, Boston, MA 02115 (bsommers@hsph.harvard.edu).

Published Online: January 3, 2019. doi:10.1001/jama.2018.20484

Conflict of Interest Disclosures: Dr Sommers reported receiving grants from National Institute of Diabetes and Digestive and Kidney Diseases, AHRQ, the Commonwealth Fund, the Robert Wood Johnson Foundation, and REACH Healthcare Foundation; nonfinancial support from Milbank Memorial Fund; and personal fees, nonfinancial support, and/or travel expenses from MetroHealth/Case Western Reserve, AcademyHealth, University of Chicago, American Economic Journal, Health Research & Education Trust, University of Cincinnati, and Northwestern Medical Center, outside the submitted work. Dr Goldman reported no disclosures.

Disclaimer: Dr Sommers previously served in the Office of the Assistant Secretary for Planning and Evaluation at the Department of Health and Human Services (HHS), but the views presented here are those of the authors and do not represent HHS.

Mazurenko  O, Balio  CP, Agarwal  R,  et al.  The effects of Medicaid expansion under the ACA: a systematic review.  Health Aff (Millwood). 2018;37(6):944-950. doi:10.1377/hlthaff.2017.1491PubMedGoogle ScholarCrossref
Goldman  AL, Woolhandler  S, Himmelstein  DU,  et al.  Out-of-pocket spending and premium contributions after implementation of the Affordable Care Act.  JAMA Intern Med. 2018;178(3):347-355. doi:10.1001/jamainternmed.2017.8060PubMedGoogle ScholarCrossref
Swaminathan  S, Sommers  BD, Thorsness  R,  et al.  Association of Medicaid expansion with 1-year mortality among patients with end-stage renal disease.  JAMA. 2018;320(21):2242-2250. doi:10.1001/jama.2018.16504PubMedGoogle ScholarCrossref
Bachrach  D, Boozang  P, Herring  A, Reyneri  D. States expanding Medicaid see significant budget savings and revenue gains. https://www.rwjf.org/en/library/research/2015/04/states-expanding-medicaid-see-significant-budget-savings-and-rev.html. Published March 22, 2016. Accessed December 20, 2018.
Sommers  BD, Gruber  J.  Federal funding insulated state budgets from increased spending related to Medicaid expansion.  Health Aff (Millwood). 2017;36(5):938-944. doi:10.1377/hlthaff.2016.1666PubMedGoogle ScholarCrossref
Brantley  E, Ku  L. Arkansas’ early experience with work requirements signals larger losses to come. The Commonwealth Fund. https://www.commonwealthfund.org/blog/2018/arkansas-early-experience-work-requirements. Published October 31, 2018. Accessed December 20, 2018.
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