Wonkblog's Sarah Kliff explains three proposals that would make good on President Obama's promise that everyone can keep their health care plan. (The Washington Post)

Twenty years ago, Congress passed a controversial law requiring states to allow people to register to vote when they applied for driver’s licenses or social services.

Now, that same law is bringing voter registration to the health insurance marketplaces, a move that some anticipate will result in legal fights and inspire even more partisan debate over the new health-care law.

According to the 1993 National Voter Registration Act, motor vehicle departments and places that provide public assistance, such as food stamps or Medicaid, or services for people with disabilities, must also offer voter registration. But states are divided over whether the law applies to the insurance marketplaces.

Hawaii concluded that its exchange was not responsible for registering new voters, while several other states, including Connecticut, Vermont and California, have designated theirs as mandated voter registration agencies. Colorado determined that the exchange is not a state agency but decided to put a voter registration link on its Web site anyway.

Even the states that have said they will offer registration vary widely on how to do so — whether to put a link on the Web site, include a form with the paper application, send forms to consumers who request them or offer a registration form to download and mail.

ACA enrollment numbers, state-by-state

The federal government, which is running exchanges for 36 states, determined that voter registration must be offered to consumers because the Centers for Medicare & Medicaid Services rules on Medicaid eligibility. Both the paper and the online applications include a line that says, “If you want to register to vote, you can complete a voter registration form at usa.gov.”

“This could end up being a huge legal battle in many states around the nation,” said Mindy Romero, who directs the California Civic Engagement Project at the University of California at Davis. “The fiercest of the debates will hinge on the impact on the electorate.”

Romero said Republicans and Democrats will be looking at how their party will benefit from the millions of potential new voters, many expected to be low income. But she said that if history of the voter law is any indicator, just because someone registers doesn’t mean they will vote — or that they will do so for any particular party. Research has shown that the national voter law had a significant impact on registration but not on turnout. And an increasing number of new voters are not identifying with one party, Romero said.

Michael Cannon, director of health policy studies at the Cato Institute, said he doesn’t have a problem with government agencies registering people to vote. But he said this effort is too selective, targeting those who are receiving free or subsidized health insurance and likely “favor the party that is in power.”

Americans for Prosperity, a conservative group that opposes the health law, said in an interview that President Obama is trying to gain political advantage by registering voters through the federal exchange.

Voting rights advocates argue that this shouldn’t be a partisan issue.

“Expanded registration is good for everybody,” said Eunice Rho, advocacy and policy counsel with the American Civil Liberties Union, which created a tool kit on implementation. “It’s good for our democracy.”

In 1993, the motor-voter law was designed to make it easier for Americans to register. States quickly challenged the constitutionality of the act or simply refused to put it into practice. The Department of Justice filed lawsuits to enforce it, and courts have consistently upheld the law.

Steven Schwinn, associate professor at John Marshall School of Law in Chicago, said offering registration through the insurance exchanges seems to fit the intent of the law. But he believes the federal government will have to decide whether to go after states that don’t agree — and it will be up to the courts to make the final interpretation.

California was the first to say it would give insurance customers the opportunity to register. Secretary of State Debra Bowen said in a letter that voter registration will help consumers “exercise the most fundamental right of citizenship.”

“It was a no-brainer,” said Nicole Winger, spokeswoman for Bowen. “There should be nothing political about encouraging people to participate in elections. Period.”

California officials said they put a link on the Web site and information on the paper application and are working with the Secretary of State’s office as they build the site.

Advocates say they hope that voter registration will take place on the ground at places such as hospitals, nonprofit organizations and community clinics, where people are signing up for health insurance with the help of enrollment counselors.

Health clinics have long helped to register voters and will continue to do so under the new health-care law, said Louise McCarthy, head of the Community Clinic Association of Los Angeles County. “It is absolutely core to the mission to empower communities,” she said.

Kaiser Health News is an editorially independent program of the Henry J. Kaiser Family Foundation, a nonprofit, nonpartisan health policy research and communication organization not affiliated with Kaiser Permanente.