The Supreme Court’s decision last June to uphold the Affordable Care Act was an important step toward achieving near-universal health care coverage in the United States. But the ruling undermined the Affordable Care Act’s guarantee of insurance coverage for Americans living near the poverty line by allowing states to opt out of the Medicaid expansion program that would have extended coverage to more than 17 million low-income Americans. As a result, several states have threatened not to expand their Medicaid programs despite the fact that the federal government would pay for 100 percent of the expansion for the first two years, gradually transitioning to 90 percent in 2020.

Interestingly—and perhaps not surprisingly—most of the states that are threatening to reject Medicaid expansion have the highest rates of uninsured women. It is probably no coincidence that these same states also have the fewest number of women in elected office, while the majority of states with the highest representation of women in elected office have chosen to expand their Medicaid programs.

The map below outlines the health needs of American women by state and indicates how well women are represented in each state legislature as their states make such crucial decisions about their access to health insurance and care. Nearly 4 million women could gain coverage in states that have yet to accept the Medicaid expansion program, but they will be left with nowhere to turn if their states reject the program.

Low-income Americans, and women in particular, face significant health disparities relative to more affluent groups in part because of inequitable access to insurance coverage and health care. In most states Medicaid currently only covers certain groups of low-income individuals—mostly working parents with incomes well below the poverty line. Because women are more likely than men to be poor and also more likely to be parenting, more women than men qualify for Medicaid under the pre-Affordable Care Act eligibility criteria. But there is still significant unmet need in access to health care coverage for low-income women living just above the income eligibility threshold for Medicaid in their state, as well as for women who are not pregnant or parenting.

To ensure that low-income Americans could gain access to the health insurance coverage they need, the Affordable Care Act expanded Medicaid eligibility to all people with incomes up to 138 percent of the poverty line—$14,856 a year for individuals—regardless of whether they are pregnant or parenting.* Of the 17 million uninsured who could become newly eligible for coverage under the Medicaid expansion, at least 7 million are women, 4 million of whom live in the states that have not yet expanded coverage.

In light of the Supreme Court decision, however, several states have chosen to opt out of the Medicaid expansion because of their ideological and political objections to Obamacare, despite the health needs of their low-income residents and the fact that it makes economic sense for them to expand. Most of the states that have indicated they will reject Medicaid expansion also have the lowest percentages of female representatives in their state legislatures. With the exception of Maine and Wisconsin, all of these states have exceptionally high rates of uninsured women. Texas, for example, has the highest percentage of uninsured women in the country, as a full 23 percent of women in the state are uninsured—nearly 1 million women would gain coverage if Texas expanded its Medicaid program.

At least 4 million of the women who would be newly eligible to gain coverage under the Medicaid expansion are of reproductive age, and the decision to reject the Medicaid expansion may have important implications for their existing family-planning coverage. The Medicaid program provides 75 percent of public funding for family-planning services in the United States—in part through Medicaid family-planning waivers that offer limited coverage for family planning to women who do not qualify for full Medicaid coverage under their state’s eligibility criteria. In six of the states that have indicated that they will not expand Medicaid, the state’s existing family-planning waivers will be one of the only lifelines for family-planning coverage for low-income residents who are uninsured. It is not clear whether those waivers will be extended past December 31, 2013, as the federal government anticipated this population of women would have full coverage through Medicaid beginning in 2014.

Nearly 4 million women would be eligible to gain coverage through Medicaid in states that have not yet committed to expanding their Medicaid program under the Affordable Care Act or that have explicitly rejected the program. Unless their states expand Medicaid, however, these women will have nowhere to turn for health care coverage. Many of the states that have not accepted the expansion also have the highest rates of uninsured women in the country and fare poorly on other health indicators such as preterm birth rates. Their governors and legislators have a responsibility to stop playing political games and stand up for women’s health in their home states.

Lindsay Rosenthal is a Research Assistant for the Women’s Health and Rights team and Health Policy team at the Center for American Progress.

* The eligibility threshold in the Affordable Care Act is 133 percent, but the law includes a special deduction to income that effectively raises the eligibility level by 5 percentage points.