AUGUSTA, Maine — Abortion providers and the American Civil Liberties Union filed a lawsuit against the state on Tuesday in a bid to overturn a longstanding rule limiting low-income women’s access to a state-funded abortion.

It’s buried in a set of rules developed in 1981 and last revised in 2010, before Gov. Paul LePage took office. However, it could set up a politically charged court fight with the anti-abortion Republican, whose spokeswoman called the lawsuit “little more than a frivolous public relations stunt.”

The lawsuit against the Maine Department of Health and Human Services was filed Tuesday morning in Cumberland County Superior Court on behalf of the state’s three abortion providers, Planned Parenthood of Northern New England, Mabel Wadsworth Women’s Health Center in Bangor and Maine Family Planning in Augusta.

The challenged rule only allows women enrolled in MaineCare — the state’s version of Medicaid, the federal-state health care program for low-income people — to have an abortion paid for by MaineCare in cases of rape, incest and life endangerment.

The ACLU and Planned Parenthood say the rule violates Maine law and the state constitution, which enumerates the rights to pursue happiness and equal protection under the law by only affecting the ability of low-income women to get an abortion and not those with private insurance.

“We think, however you feel about abortion, it’s not fair to have a two-tiered system,” said Zachary Heiden, an ACLU of Maine lawyer.

The rule is a rare example of restrictive abortion policy in Maine, which has some of the most permissive abortion laws in the country, according to the pro-abortion rights Guttmacher Institute.

But Maine is in the nation’s mainstream on public abortion funding. The Hyde Amendment limits federal money from being spent on abortion except in cases of rape, incest or life endangerment. States can choose to fund other abortions themselves.

Maine is one of 32 states that has chosen to stick roughly to federal law, according to Guttmacher. Of the 17 states that cover other abortions, only four did so voluntarily and 13 — including Vermont and Massachusetts — were court-ordered.

LePage spokeswoman Adrienne Bennett noted Maine’s adherence to federal policy in a statement in response to the lawsuit posted on her Facebook page on Tuesday morning, calling the rule “well established law.”

It’s unclear who will represent the state in the matter. Attorney General Janet Mills, a pro-abortion rights Democrat, hasn’t reviewed that with DHHS Commissioner Mary Mayhew, said Tim Feeley, Mills’ spokesman.

One-third of the Mabel Wadsworth Center’s 1,400 annual patients — 400 of whom receive abortion services — are either on MaineCare or would qualify if they got pregnant, and issues with abortion access have been exacerbated as the center sees “more and more people struggling to make ends meet,” said Andrea Irwin, the center’s executive director.

“We think it’s important that no matter how much money you make, you have access,” she said.

Michael Shepherd joined the Bangor Daily News in 2015 after time at the Kennebec Journal. He lives in Augusta, graduated from the University of Maine in 2012 and has a master's degree from the University...