NASHVILLE (AP) - A federal judge on Friday ordered a recount of votes on a 2014 amendment to the Tennessee Constitution that made it easier to put restrictions on abortions.

U.S. District Judge Kevin Sharp ruled that the method used to tabulate the votes on the amendment was "fundamentally unfair" to the eight Tennesseans who filed a lawsuit challenging the election results. Those who sued maintained that the state incorrectly interpreted the way the votes should be counted and tallied them in favor of abortion opponents.

"At issue," Sharp's ruling says, is the language in a 172-year-old sentence that says an amendment will become part of the state constitution "if the people shall approve and ratify such amendment or amendments by a majority of all the citizens of the state voting for governor."

The voters who filed the lawsuit have argued that state officials tabulated the results without considering who voted for governor. They ma intained that it wasn't just enough to consider whether more voters approved of the amendment than not; it had to be by a majority of the number of people who cast ballots in the governor's race. For example, if 1 million people voted in the governor's race, at least 500,001 would have to cast a ballot for the amendment.

The state attorney general's office has argued that Tennessee has been counting votes on amendments the same way for more than 100 years. A spokesman for state election officials said in an email that he could not comment on pending litigation.

Sharp agreed with the plaintiffs and ordered officials to recount the votes to determine whether the amendment passed by a majority of those who voted for governor.

Sharp's decision comes the day after a state court judge in Williamson County ruled in favor of the way Tennessee counted the ballots.

Sharp has given state officials 20 days to give him a timeline on the recount.

The constitut ional amendment was declared passed with 53 percent of the vote. It said that nothing in the state constitution "secures or protects a right to abortion or requires the funding of an abortion." It gave power to state lawmakers to "enact, amend, or repeal statutes regarding abortion, including, but not limited to, circumstances of pregnancy resulting from rape or incest or when necessary to save the life of the mother."