The Supreme Court on Wednesday ruled the vote disparity in the July 2016 Upper House election to be constitutional, following more than a dozen conflicting rulings from lower courts.

The July 10 House of Councilors election was held with a disparity in the weight of votes of up to 3.08 times between the most and the least populated constituencies, a smaller gap than in previous elections held before the latest electoral district mergers.

The top court’s 15-member Grand Bench, led by Chief Justice Itsuro Terada, said the vote disparity “was not in a state of extreme inequality that would generate issues of unconstitutionality.”

Two groups of lawyers had filed a total of 16 suits across the nation, claiming the vote disparity, in which one vote carried the weight of up to three votes when comparing the two extremes, violated the constitutionally-guaranteed equality under the law, and that the election results should therefore be invalidated.

Ten high courts went on to rule that the election was held in a “state of unconstitutionality,” while six others ruled it was constitutional, prompting the Supreme Court to weigh in on the issue.

The top court previously ruled that the 2010 and 2013 Upper House elections — in which the weight gap had reached up to 5.00 times and 4.77 times, respectively — were held “in a state of unconstitutionality” and urged parliament to review the demarcation of Upper House districts.

Upper house constituencies were originally demarcated on the basis of prefectures. But after the previous top court ruling, the country redrew them by merging two pairs of less-populated prefectures — Tottori and neighboring Shimane as well as Tokushima and neighboring Kochi — into two electoral districts.

As a result, the vote weight gap was slashed to around 3 times in the July 2016 election.

But the 10 high courts considered the weight gap still “in a state of unconstitutionality.” The Okayama branch of the Hiroshima High Court, for example, said the 2015 constituency mergers, which only affected four prefectures, were insufficient.

In the latest case that reached the Supreme Court, an election board disputed plaintiffs’ claims, saying Upper House lawmakers tend to represent their local areas, and that the current electoral system that in principle retains prefecture-based districts is reasonable.