The re-demarcation of Lower House electoral districts proposed by a government council to Prime Minister Shinzo Abe last week would be the most sweeping one since the current electoral system was introduced in the mid-1990s, redrawing the borders of a total of 97 single-seat constituencies in 19 prefectures. It’s part of a scheme to narrow the disparity in the value of votes between populous and less populous districts — which hit 2.13 to 1 at its maximum in the 2014 general election — by eliminating one Lower House seat each from six prefectures and rejiggering electoral districts elsewhere. It’s estimated this would reduce the maximum vote value gap to 1.999 to 1 under the population forecast for 2020.

The implementation of the proposed changes would be a massive operation — not just for the Lower House members elected from affected constituencies, particularly incumbents from Abe’s Liberal Democratic Party who face a game of musical chairs with their colleagues — but also voters, who must be fully informed on how their electoral districts will change to eliminate confusion.

However, the proposed changes wouldn’t be the end of the story. The electoral reform legislation enacted last year calls for the further redistribution of Lower House seats across constituencies under a mechanism that better reflects the regional population breakdown — as proposed by a panel of experts commissioned by the Lower House speaker — based on data from the next national census in 2020.

A disparity in the value of votes means that a vote cast in one constituency carries more weight in choosing a lawmaker than a vote cast in another — thus distorting the representation of popular will in the Diet — because the composition of the electoral districts does not reflect the population dispersal. The Supreme Court has ruled that the gap in the value of votes in the last three Lower House elections in 2009, 2012 and 2014 — when the maximum disparity was wider than 2 to 1 — was “in a state of unconstitutionality” that violated the principle of equality under the Constitution, although it fell short of invalidating the general election results.

When the experts panel proposed the new method of distributing the Lower House seats last year as a solution to the problem, the LDP balked on its immediate introduction — because that would have hit large numbers of the party’s incumbent lawmakers elected from the constituencies to be affected — and opted instead for a stopgap reform that brings the vote gap disparity barely within 2 to 1. The more radical redistribution of the Lower House seats was thus postponed until after the 2020 census as the LDP put priority on its partisan interests.

At the same time, the redistribution of Diet seats and re-demarcation of electoral districts will likely be an endless process if they are tied to the population shift. The population flight from rural areas to urban metropolis continues unabated, and rural areas will see their Diet representation further dwindle if the current demographic trend continues. Under the Constitution, Diet members are “representatives of all the people,” not exclusively the voters who elected them. The value of votes should be made as equal as possible across constituencies. But charges that redistributing Diet seats solely according to the population will leave voters in rural areas increasingly unheard in national politics could make the process difficult at some point. How to reconcile ensuring equality in the value of votes and securing Diet representation to voters in depopulated areas will be an issue that has to be addressed by overhauling the election system itself. That may involve reviewing the different roles and functions of the Lower House and the Upper House, and adapting the electoral system in each chamber accordingly.

The current Lower House electoral system combining single-seat electoral districts — whose numbers will be reduced from 295 to 289 nationwide in the latest reform — and regional proportional representation blocs was introduced in the 1996 general election, replacing the previous system in which multiple seats were allocated to each constituency. Under the winner-take-all races in single-seat constituencies, the victorious party tends to grab a much greater portion of Diet seats than its share of the popular vote — a problem that has been highlighted in the results of recent general elections. That, along with the question of equality in the value of votes, should be considered in a comprehensive reform of the electoral system, for which lawmakers and parties should start preparing.