Attorneys general from 20 states and the District of Columbia have joined Kentucky Attorney General Andy Beshear in defending a federal court ruling last year that allowed Kentucky's only abortion clinic to stay open.

The attorneys general, all Democrats, have filed briefs with the 6th U.S. Circuit Court of Appeals in support of last year's ruling by U.S. District Judge Greg Stivers, who found unconstitutional a 1998 state law that requires abortion clinics to have signed agreements with an ambulance service and a hospital in the event of an emergency.

Gov. Matt Bevin's administration had used the law to try to shut down EMW Women's Surgical Center in Louisville, saying their agreements were insufficient.

In a case that has generated national interest and is split on party lines, this week's "friend of the court" briefs by Democrats follow a filing in February by 16 Republican attorneys general, arguing the opposite — that Kentucky's law should be upheld.

Indiana Attorney General Curtis T. Hill Jr., who led the Republican filing along with Ohio Attorney General Dave Yost, sided with the Bevin administration's argument for upholding Kentucky's law.

“Under the Constitution, states have the authority to pass and enforce reasonable laws,” Hill said in a statement on his website. “Requiring abortion clinics to maintain basic health and safety standards falls well within a state’s prerogative.”

But in a tweet Thursday, Nevada Attorney General Aaron Ford, leading the Democrats' brief, said he is "proud to lead a multi-state effort to protect women's access to healthcare services."

Stiver's ruling followed a challenge to the law by EMW, the state's only abortion provider, and Planned Parenthood of Indiana and Kentucky, which is seeking a license to offer abortions at its clinic in Louisville.

Lawyers for Bevin, an anti-abortion Republican seeking a second term, have asked the Cincinnati-based appeals court to overturn Stivers' decision.

Beshear, a Democrat who is running for governor, filed a separate brief in support of striking down the regulation the Bevin administration created and relied on in seeking to close the clinic. But he argued it's not necessary to strike down the underlying state law, which he said had been in effect since 1998 without infringing on women's rights.

Beshear said in an April 3 statement that it is his duty as attorney general to uphold the state and U.S. constitutions.

"By ignoring state and federal laws, the governor's actions threaten the health and safety of women," he said.

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A Bevin spokesman blasted Beshear for joining the side of "pro-abortion forces."

"Attorney General Beshear reached a new low" by filing the brief, said spokesman Woody Maglinger.

The Bevin administration had used the law to try to close EMW and to deny Planned Parenthood a license to provide abortions, according to testimony at trial. It claimed that the "transport" and "transfer" agreements EMW and Planned Parenthood had obtained with hospitals and ambulance services were deficient under the law.

EMW and Planned Parenthood claimed the Bevin administration was imposing new standards for the agreements beyond what the law required, and that would make it impossible for them to qualify for a license.

In a separate action filed last month, Planned Parenthood is asking a judge to hold the Bevin administration in contempt of court for continuing to refuse it a license to provide abortions now that the law requiring transfer and transport agreements has been struck down.

The state Cabinet for Health and Family Services, which oversees abortion clinics, has blamed Planned Parenthood, saying it failed to follow proper steps to obtain the license.

Thursday's filing by the Democratic attorneys general said state regulation of abortion "must not serve as a mere pretext for suppressing women's constitutional rights."

They argue that such a law is unconstitutional if it is used by a state to limit access to abortion. The brief also rejected one of the key arguments the Bevin administration made at trial — that women in Kentucky could easily travel to one of several bordering states for abortion services should the state lose its only clinic.

"Kentucky's geographical features do not permit Kentucky to violate the constitutional rights of women within Kentucky's borders," its brief said.

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The Republican attorney generals in their brief argued states have a right to impose regulations on abortion clinics and that in striking down's Kentucky's law, the federal judge "failed to consider the general benefits" of the law.

"States have no duty to facilitate abortions by carving out exceptions to generally applicable laws," it said.

Stivers' ruling found Kentucky's law to be unconstitutional in that the transfer and transport agreements were unnecessary and posed a barrier to women seeking legal abortions.

"The evidence presented here establishes clearly that scant medical benefits from transfer and transport agreements are far outweighed by the burden on Kentucky women seeking abortions," Stivers' opinion said.

The appeals court has not set a date for hearing arguments on the appeal.

Lawyer Michael Abate, who represents Planned Parenthood, said the case may be attracting an unusual level of outside interest from groups who support the lower court ruling because of the argument women in Kentucky could simply travel to another state for an abortion.

"Obviously, these states see this as a very important issue," Abate said. "They don’t want other states offloading their obligations under the constitution to other states. These states are taking a strong stand that that's not the way the constitution works. Every state is bound by it."

This story has been updated to reflect that Attorney General Andy Beshear is seeking to strike down an abortion clinic regulation created by the administration of Gov. Matt Bevin.

Deborah Yetter: 502-582-4228; dyetter@courierjournal.com; Twitter: @d_yetter.