A recent rise in approval ratings for his Cabinet has strengthened speculation that Japanese Prime Minister Fumio Kishida may dissolve the House of Representatives soon after the Group of Seven summit in his constituency of Hiroshima from next Friday.

The ruling Liberal Democratic Party, headed by Kishida, won four of the five Diet seats up for grabs in by-elections in late April, as voters appear to have given high marks to his diplomatic efforts, such as improving ties with South Korea and a surprise visit to Ukraine.

But it remains to be seen whether the LDP will be able to increase its seats in a potential snap election, as it only managed to win the by-elections by a narrow margin and lost in a constituency to a growing opposition party based in Osaka.

Japanese Prime Minister Fumio Kishida visits the venue for the forthcoming Group of Seven summit in Hiroshima, western Japan, on May 13, 2023, to meet police officers and Japan Coast Guard officials in charge of security during the May 19-21 event. (Kyodo) ==Kyodo

As Kishida seeks re-election in the LDP presidential race in September 2024, he would face a challenging decision on the timing of dissolving the lower house, given the lack of a definite assurance that his party will emerge victorious in the election.

After the ruling party's triumph in the House of Councillors election in July 2022, Kishida, who became the president of the LDP in September 2021, was widely credited with enjoying a "golden three years" without any national elections.

The next upper house election is scheduled for the summer of 2025. The current four-year terms for lower house members expire in October of that year unless a prime minister chooses to dissolve the chamber under a provision of the Constitution.

Late last year, Kishida's grip on power was shaken by revelations of relations between LDP lawmakers and the controversial Unification Church religious group as well as resignations of four Cabinet members due partly to political funding scandals.

His Cabinet's support rate sank to what is seen as the "danger level" of 30 percent, but it has been clearly picking up since Kishida held talks with South Korean President Yoon Suk Yeol in Tokyo and visited Ukraine, under invasion by Russia, in March.

In late April, some media polls showed the Kishida Cabinet's approval ratings had recovered to around 50 percent and the LDP won the by-elections, possibly prompting the premier to move forward the timing of dissolving the lower house, ruling lawmakers said.

Political pundits, however, said that upon careful examination of the number of votes the LDP garnered, the results of the by-elections are not considered a "resounding victory" for the party.

In an upper house district, a candidate backed by the LDP defeated her rival only by a slight margin of about 300 votes. In a constituency in the lower house, the LDP edged out its opponents as they failed to settle on a unified candidate.

Looking back on the by-elections, an LDP lawmaker who previously served as a Cabinet member cautioned against calling a snap election, saying, "Dissolving the lower house solely based on the rebound in approval ratings would be premature and hasty."

Another annoyance for Kishida may be a surge in prominence of the Japan Innovation Party, viewed as the true winner in a series of elections in April, including local polls. The party is keen to become the main opposition force in the next general election.

The regional political group Osaka Ishin no Kai, the origin of the Japan Innovation Party, was set up in 2010 with its signature platform known as the "Osaka metropolis plan." The blueprint was designed to achieve cost-effective governance by eliminating duplication of work by the Osaka prefectural and city governments.

The initiative was voted down twice at local referendums in 2015 and 2020, but the reform-minded party, now led by lower house lawmaker Nobuyuki Baba, has steadily expanded its support base beyond Osaka. Baba began his political career as an LDP member.

Japanese Prime Minister Fumio Kishida (C) waves to tourists during a visit to the World Heritage-listed Itsukushima Shrine in Hatsukaichi in Hiroshima Prefecture, western Japan, ahead of the May 19-21 Group of Seven Hiroshima summit he will chair. (Kyodo) ==Kyodo

In April, a Japan Innovation Party candidate beat a rival endorsed by the LDP in the lower house by-election in Wakayama and another secured the governorship in Nara, respectively. Both prefectures are in the Kansai region, with Osaka as its center.

Eventually, the Japan Innovation Party extended its reach by acquiring 774 local leaders and assembly members across the country, gaining from 468 as of early February, with the opposition politician in Nara becoming the group's first-ever governor outside of Osaka.

The LDP and other parties have been wary of the preparations made by the Japan Innovation Party for the next general election, as its secretary general, Fumitake Fujita, has pledged to field candidates in all 289 electoral districts.

Nevertheless, Nozomu Yamazaki, a professor of political theory at Komazawa University, said the party's impact on Kishida's decision regarding when to dissolve the lower house is limited, saying its influence has not yet spread nationwide.

Observing the shared conservative policies between the LDP and the Japan Innovation Party, such as national defense and amending the pacifist Constitution, Yamazaki said Kishida "does not perceive it as a threat capable of toppling his party from power."

Assuming he successfully hosts the three-day G-7 summit in Hiroshima, approval ratings for his Cabinet are set to increase further, but Yamazaki added that any positive effects on Kishida's popularity are likely to be short-lived.

It would be a risky gamble for Kishida to call a general election on the only grounds of the support rate for his Cabinet rising after the G-7 summit, which would not be "powerful enough to lead the party to an overwhelming victory," Yamazaki said.

Related coverage:

Dissolving lower house not being considered for now: Japan PM Kishida

LDP wins 4 of 5 Diet by-elections amid snap election speculation

Japan split over parliament debate on Constitution revision: poll