An anti-abortion advertisement stands posted in Lorain, Ohio, U.S., November 1, 2024. / Reuters/Shannon Stapleton

(Reuters) - Republicans retained their majority on Ohio's top court and are leading in a race to unseat a sitting Democratic justice on North Carolina's following an election cycle in which Democrats had hoped the issue of abortion access would help liberal candidates secure seats on state supreme courts nationwide.

Democratic-backed candidates in Kentucky and Michigan won contests for seats on those states' respective high courts in which reproductive rights were a key issue. But Arizona voters declined to kick two Arizona Supreme Court justices who had upheld an 1864 abortion ban off the bench in a retention election, according to projections from Edison Research.

Those races were in the 33 states nationwide where supreme court seats were on the ballot in Tuesday's election either through competitive elections or votes to retain appointed jurists.

The mixed outcomes followed costly campaigns by groups that support abortion rights such as Planned Parenthood and the American Civil Liberties Union to influence the outcome of down-ballot races for state supreme courts.

The conservative-majority U.S. Supreme Court's 2022 reversal of its 1973 Roe v. Wade ruling, which had established a nationwide right to abortion, moved the fight over reproductive rights to the states, clearing the way for abortion bans in 13 conservative states and restrictions in others. 

The decision raised the stakes for elections to determine who sits on state supreme courts that have the final word on interpreting state constitutions.

"If you are a conservative or a progressive, you look at last night's supreme court elections and see mixed results," said Douglas Keith, a senior counsel at the Brennan Center for Justice who tracks judicial elections.

He said the differences in outcomes appeared to turn in part on whether the races were partisan or non-partisan and suggested voters may have been more open to a pro-abortion rights message when a party label did not appear on the ballot next to a candidate's name.

Voters approved state constitutional amendments enshrining or expanding abortion rights in seven of the 10 states where they appeared on the ballot on Tuesday, including Missouri, one of 13 states with an abortion ban. 

Similar measures failed in Florida, Nebraska and South Dakota, marking the first time voters rejected pro-abortion rights measures since Roe v. Wade was overturned.

Supporters of abortion rights similarly fell short in their bid to flip control of the Ohio Supreme Court, where a Republican majority will expand to 6-1 after Republican incumbent Justice Joseph Deters and candidates Megan Shanahan and Dan Hawkins defeated Democratic incumbent Justices Melody Stewart and Michael Donnelly and candidate Lisa Forbes.

The Democrats in their campaign highlighted the issue of abortion even after Ohio voters last year approved a constitutional amendment guaranteeing abortion rights.

Democratic-backed candidates fared better in Michigan, where incumbent Justice Kyra Harris Bolden and University of Michigan law professor Kimberly Ann Thomas headed off a bid by two Republican-supported opponents in the nonpartisan election to flip the ideological balance of that court.

The result bolstered the already existing 4-3 majority of Democratic-backed justices by one, as Bolden was elected to replace retiring Republican Justice David Viviano.

In North Carolina, the race for a seat on the state high court appeared headed to a recount, with Republican North Carolina Court of Appeals Judge Jefferson Griffin narrowly leading Democratic Justice Allison Riggs, who campaigned on the issue of reproductive rights.

Griffin describes himself as "an originalist and a textualist," referring to legal doctrines embraced by conservative jurists. With all precincts reporting, he was leading 50.09 percent by just 9,851 votes, a razor-thin margin that under state law could prompt a recount.

In Kentucky, Court of Appeals Judge Pamela Goodwine, who was endorsed by Democratic Governor Andy Beshear and Planned Parenthood, defeated conservative opponent Erin Izzo to become the first Black woman elected to the seven-member court.

Conservative groups opposed to three Oklahoma Supreme Court justices they deemed too liberal meanwhile narrowly convinced voters to unseat one, Yvonne Kauger. Oklahoma has an abortion ban, but the court in a 5-4 decision that Kauger joined in March found the state's constitution protects a right to an abortion to preserve the mother's life.