Jill Stein, the presidential candidate for the Green Party, will remain on the ballot in Wisconsin, the state’s Supreme Court said, after the court declared a Democratic technical challenge to her ballot access moot on Monday.

The three-page order, left unsigned by members of the court, represented a significant victory for Ms. Stein’s third-party presidential bid, as the Green Party had been disqualified from the ballot in Wisconsin in 2020. The presence of Ms. Stein — a minor left-wing candidate — on the ballot could also pose a risk to Vice President Kamala Harris’s prospects in Wisconsin, which has been won on razor-thin margins in recent presidential races.

David Strange, a staff member of the Democratic National Committee, filed a complaint to the Wisconsin Elections Commission this month asserting that the Green Party was ineligible to place a presidential candidate on the ballot because the party had no candidates for state office, or state officeholders, who could nominate presidential electors — those who officially cast votes for a presidential candidate in the Electoral College.

The order by the state’s Supreme Court, which offered few details for its reasoning, said that it had determined “that the petitioner is not entitled to the relief he seeks” and that “all other pending motions are denied as moot.”

An election last year in Wisconsin, the most expensive judicial election in American history, was won by a liberal judge and tipped the balance of the court from the conservatives.

The decision on Monday represents the latest legal battle over ballot access for third-party candidates, which both Democrats and Republicans believe could shape the outcome of the election by pulling support from Ms. Harris and former President Donald J. Trump in key states like Wisconsin. Democrats had made significant efforts to undermine Robert F. Kennedy Jr.’s ballot access — concerned that he could draw more support from Democrats than Republicans — before he ended his independent presidential candidacy and backed Mr. Trump.

In 2016, Hillary Clinton lost to Mr. Trump in Wisconsin by a margin of 22,748 votes. Ms. Stein, who was also the Green Party candidate in 2016, won 31,072 votes while Gary Johnson, the Libertarian Party candidate, won 106,674 votes that year. Mr. Biden won the state by 20,682 votes in 2020 after the Green Party candidate failed to qualify.