The 4-3 ruling came a month before the state’s Aug. 9 primaries, when voters will narrow the fields for governor and U.S. senator. Both contests in this battleground state are being closely watched nationally.

For years, ballot drop boxes were used without controversy across Wisconsin. Election clerks greatly expanded their use in 2020 during the coronavirus pandemic as absentee voting hit unprecedented levels.

By the time of the presidential election, more than 500 ballot drop boxes were in place across Wisconsin. Some Republicans balked at their use, pointing to a state law that says an absentee ballot must “be mailed by the elector, or delivered in person, to the municipal clerk issuing the ballot or ballots.”

The state’s high court on Friday ruled that means voters themselves must return absentee ballots and cannot use drop boxes.

“The key phrase is ‘in person’ and it must be assigned its natural meaning,” Justice Rebecca Bradley wrote for the majority.

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In a dissent, Justice Ann Walsh Bradley called the majority “dangerous to democracy.”

“It has seemingly taken the opportunity to make it harder to vote or to inject confusion into the process whenever it has been presented with the opportunity,” she wrote.

The two Bradleys on the court are not related.

The majority opinion flatly stated “ballot drop boxes are illegal under Wisconsin statutes” without distinguishing between those that are staffed and those that are unstaffed. The dissenters said they considered the matter unresolved because the lower court found that drop boxes that were staffed and in clerk’s offices could be used.

The case started last year when the conservative Wisconsin Institute for Law & Liberty brought a lawsuit over the use of drop boxes on behalf of two suburban Milwaukee men. State law does not mention ballot drop boxes and the lawsuit argued their use “causes doubts about the fairness of the elections and erodes voter confidence in the electoral process,” and that the two men “are entitled to have the elections in which they participate administered properly under the law.”

State election officials and disability rights advocates who intervened in the case defended the use of drop boxes, saying they offered a way for voters to return ballots in person. In addition, they contended nothing in state law bars voters from having their spouse, a friend or someone else deliver their completed ballot to a clerk so it can be counted.

In January, Waukesha County Circuit Judge Michael Bohren ruled in favor of those who brought the lawsuit. He concluded state law did not allow unstaffed ballot drop boxes and required absentee voters to return their ballots in person or place them in mailboxes themselves.

The state Supreme Court blocked Bohren’s order for judicial and school board primaries in February because they were fast approaching. But the justices barred the use of drop boxes for the general elections for those offices in April.

On Friday, the court sided with the lower court and issued a more permanent ruling that will affect future elections, starting with next month’s primaries. Clerks began mailing absentee ballots last month.

Thirty states and the District of Columbia allow ballot drop boxes, according to the U.S. Vote Foundation. Thirty-one states have laws allowing voters to have someone else return their ballot for them, according to the National Conference of State Legislatures. Some of those states allow voters to designate whoever they want for that role, while others limit it to family members or caregivers.

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Wisconsin law says no person may “receive a ballot from or give a ballot to a person other than the election official in charge.” Those bringing the lawsuit argued that policy must be strictly followed, meaning it would be illegal for someone to drop their elderly parents’ ballots off for them or for church members to gather ballots after a service and then take them to a clerk’s office.

The majority agreed with that assessment.

Republicans have been most concerned about large-scale efforts to collect ballots by partisan actors. While some have engaged in that practice in other states, neither side deployed extensive operations for ballot collection in Wisconsin in 2020, when Joe Biden narrowly defeated President Donald Trump in the state.

The lower court ruled that ballots returned by mail could be placed into mailboxes only by voters themselves — a finding that alarmed advocates for the disabled because some voters physically cannot get to the polls or place their ballots in the mail.

The Supreme Court didn’t go as far, saying for now it would not address whether a voter can have someone else place a ballot in the mail.

Rick Esenberg, the president of the group behind the lawsuit, in a statement said the ruling “provides substantial clarity on the legal status of absentee ballot drop boxes and ballot harvesting.”

The decision fell along ideological lines, with the justices elected with support from Republicans in the majority and justices elected with support from Democrats in dissent.

Both sides were closely watching Justice Brian Hagedorn, who won a 2019 race with the help of Republicans but in a series of high-profile cases has sided with the court’s three liberals.

Hagedorn signed onto much of Bradley’s decision, giving conservatives the four votes they needed for a majority.

In a concurring opinion, Hagedorn urged lawmakers to clarify the state’s election laws, some of which were first enacted more than a century ago.

“Some citizens will cheer this result; others will lament,” he wrote of the majority decision. “But the people of Wisconsin must remember that judicial decision-making and politics are different under our constitutional order. Our obligation is to follow the law, which may mean the policy result is undesirable or unpopular. Even so, we must follow the law anyway.”