While the Cabinet of Prime Minister Shinzo Abe enjoys high support rates, hovering around 70 percent, its very legitimacy is being questioned.

More than a dozen high courts have handed down rulings confirming that vote-value disparities tainted the Dec. 16 general election that returned Abe’s Liberal Democratic Party to power. Notably, the Hiroshima High Court ruled last month that the results of two electoral districts were invalid, the first time this has happened.

On April 12, the LDP and its junior coalition partner, New Komeito, submitted a bill aimed at rectifying the disparities by taking one Lower House seat away each from five prefectures with relatively low populations.

But many doubt this will be enough to eliminate the problem, which also plagues the Upper House, facing an election in July.

Here are several issues related to the vote-value disparity.

What is the nature of vote-value disparity?

The disparity refers to the ideal principle that the electoral system should not allow one person to have more than one vote. Differences in the population density of each constituency, however, can alter the amount of representation they have in the Diet. Thus, the more voters a constituency has, the less each vote counts.

While the Constitution does not set a threshold for such disparities, the Supreme Court has historically ruled that vote values are unconstitutional or “in a state of unconstitutionality,” once the disparity among constituencies exceeds around 3-to-1.

In 1994, a government panel on Lower House constituencies was set up to reorganize contituencies to keep the gap under 2-to-1.

What will happen to lawmakers elected in areas where voting results were invalidated?

Election results in three of the 31 constituencies the high courts ruled on were declared invalid. However, this does not mean the lawmakers will automatically be unseated.

The ruling won’t take effect in Hiroshima district Nos. 1 and 2 until Nov. 27, a year after the government panel began planning to reorganize the seats.

And even though the Okayama Branch of the Hiroshima High Court immediately voided the election results in Okayama’s No. 2 district, nothing will happen until the Supreme Court rules on the three invalidated districts and the other 28 constituencies, since local election boards are appealing the rulings to the Supreme Court.

Masato Tadano, a law professor at Hitotsubashi University, said if the Supreme Court upholds the invalidation of the three districts’ results, it’s likely all 31 will go the same way in a unified ruling.

If this happens, the constituencies will have 40 days to hold another election, according to the Public Offices Election law. The Supreme Court is expected to deliver its verdict as early as this fall.

But even if a lawmaker is unseated, it won’t affect any legislation he may have voted on.

What is causing the disparity?

When the Supreme Court ruled in March 2011 that the 2009 Lower House election was in a state of unconstitutionality because of vote disparities, it blamed the electoral system, which allocates a single seat to each of the 47 prefectures and adds more in proportion to each prefecture’s population — a scheme Japan calls proportional representation.

The Supreme Court urged the Diet to establish a new system that better reflects the way the nation’s population is distributed.

The current electoral system debuted in 1994, after Japan decided to switch from multiple-seat constituencies to a combination of single-seat and proportional-representation systems in preparation for establishing a two-party political system. The single-seat system was expected to mitigate the LDP’s factional politics, a power game in which cliques in the party tended to pit LDP members against each other in the same constituencies.

What’s the plan to rectify it?

Following the 2011 Supreme Court ruling, the then-ruling Democratic Party of Japan and the LDP-New Komeito opposition bloc struck a deal to change the number of seats.

On Nov. 16 — the day then-Prime Minister Yoshihiko Noda dissolved the Lower House — a bill to reduce the number of single-seat constituencies in the Lower House to 295 from 300 cleared the Diet.

On April 12, the LDP-New Komeito ruling coalition submitted a bill to cut seats from Fukui, Yamanashi, Tokushima, Kochi and Saga prefectures, and reorganize 42 constituencies in 17 prefectures to bring the vote-value disparity down to 1.998 from 2.524, as urged by a government panel.

Is cutting five seats enough?

Not quite. Experts agree that the bill is just a stop-gap solution.

The current bill has been criticized for essentially preserving the old, flawed system.

For example, Tottori Prefecture, which has the smallest population in the nation based on the 2010 census, will still have two seats — one more than it should. Experts say Tottori should have less than two seats if constituencies are correctly distributed according to population.

“What the Supreme Court demanded is not a makeshift measure, but something that could bring the disparity below 2-1 for a long time,” said Tadano. “It also demands the constituencies to be allocated in proportion to the population.”

In the Lower House, one seat is unconditionally allocated to each of the 47 prefectures before the rest are distributed in proportion to their population.

To fundamentally change the system — to reallocate the 300 single-seat constituencies in the 480-seat Lower House strictly based on population — 21 seats would have to be shifted. Tokyo would get six more seats, Kanagawa three more, and 21 prefectures would lose one each.

But reducing the number of seats in rural areas would be disadvantageous to the parties that hold sway there, particularly the LDP, which holds a majority in the powerful Lower House.

What is the opposition’s stance on the ruling coalition’s bill?

The DPJ, Your Party and Nippon Ishin no Kai (Japan Restoration Party) oppose it and are calling for more drastic and fundamental reform.

The DPJ is pushing a plan to eliminate 30 single-seat constituencies and 50 from proportional representation.

The LDP-New Komeito ruling bloc, however, is upset because the DPJ voted for the five-seat reduction last November, when Noda was being forced by the opposition to call a snap election.

Does the Upper House also have a vote disparity problem?

Last October, the Supreme Court ruled that the 2010 Upper House election was unconstitutional because the vote-value disparity had reached a whopping 5-to-1 ratio.

It wasn’t the first time. In 1996, the Supreme Court also ruled the 1992 Upper House election unconstitutional for the same reason.

The group of lawyers challenging the validity of the 2009 Lower House election is reportedly planning to file similar suits in all 47 prefectures after this summer’s Upper House poll in July.

Tadano, the expert at Hitotsubashi University said the widening disparity in the Upper House presents a growing problem because the chamber is gaining legislative power.

“It used to be fine with a 5-to-1 or 6-to-1 disparity due to the weaker power in the Upper House, but now the disparity should not be overlooked, given the clout the Upper House can exercise in the currently lopsided Diet,” he said.

What is the situation in other countries?

In the United States, the Constitution unconditionally and evenly allocates two Senate seats to each state, no matter the population. Thus the vote-value disparities in the upper chamber are huge by default.

In Japan’s Upper House, on the other hand, half of the 242 seats are up for re-election every six years. Of the 121 seats up for grabs, 73 are distributed to the 47 prefectures in rough proportion to population, while the other 48 are allocated by proportional representation.

In the U.S., the seats in the much larger House of Representatives are apportioned to each state only by population, limiting the vote-value disparity to just 1.88.

In France, two seats used to be unconditionally allocated to each of its departments (states). As a result, the disparity became as great as 5-to-1. The Constitutional Court scrapped the system, closing the gap to 2.37.

While differing social and political systems make it difficult to draw a simple comparison among different countries, Tadano says that more are choosing to distribute seats in proportion to the population.

“The global trend favors a system to distribute seats in accordance with the population ratios, especially in the Lower House,” said Tadano.

The Weekly FYI appears Tuesdays. Readers are encouraged to send ideas, questions and opinions to hodobu@japantimes.co.jp