NASHVILLE (AP) — Opponents of a constitutional amendment that has enabled tougher abortion restrictions in Tennessee are appealing to the U.S. Supreme Court for a recount, saying the state's quirky method for counting votes on ballot measures unfairly compels citizens to make one choice dependent on another.

The method denies majority rule on ballot measures if the "yes" votes don't exceed more than half of total votes cast in the same ballot's governor's race. And in 2014, it prompted efforts to game the system by campaigns both for and against Amendment 1. Supporters urged voters to leave the governor's race blank to lower the bar, while opponents sought to increase voting for governor.

The amendment says nothing in the state constitution "secures or protects a right to abortion or requires the funding of an abortion" and empowers state lawmakers to "enact, amend, or repeal statutes regarding abortion." A series of laws passed since then have made abortions more difficult to obtain in Tennessee.

Tennessee has counted constitutional amendments the same way for more than a half-century, state officials told the court.

In 2014, the abortion measure passed with 53 percent of the vote, and the overall count surpassed turnout in the re-election of Republican Gov. Bill Haslam, so the amendment was ratified.

In the Supreme Court petition, the abortion amendment opponents question the vote-counting method and ask if Tennessee officials overstepped by filing their own suit after the federal challenge was already filed. The state court offered a favorable ruling for Tennessee officials.

"This case raises the important question of whether and to what extent a state's administration of an election survives Fourteenth Amendment scrutiny when it tilts the field by both compelling voters on one side of an issue to vote in another, separate race and by strongly incentivizing voters on the other side of the same issue to avoid voting in that separate race," the petition states.

The federal challenge of the vote count had remained in limbo for years, offering state lawmakers no certainty of whether new or proposed restrictions would ultimately later be wiped from the books.

In April 2016, a district court ruling sided with the eight voters that sued the state and he ordered the recount. The judge called Tennessee's vote-counting unconstitutional and fundamentally unfair.

In the court-ordered recount, officials were ordered to tally amendment votes only from people who also voted for governor. But that recount was put on hold pending the appeal.

The 6th U.S. Circuit Court of Appeals overturned the recount decision in January, ruling that the state's vote tabulating method was reasonable and true to the meaning of the state constitution and didn't infringe on plaintiffs' voting rights.