Prime Minister Yoshihide Suga's abrupt decision to resign marks the beginning of a tumultuous few months in Japanese politics, with ambitious lawmakers in the ruling party already positioning themselves to become his successor.

The Liberal Democratic Party is set to choose its new leader on Sept. 29, a vote that will effectively determine the next prime minister and have major implications for an all-important general election this fall. The LDP leader concurrently serves as premier as the party controls the House of Representatives.

Two contenders have already thrown their hats in the ring -- former Foreign Minister Fumio Kishida and former internal affairs minister Sanae Takaichi -- with vaccination minister Taro Kono also preparing to announce his candidacy.

Former internal affairs minister Seiko Noda has also expressed her eagerness to run, while former Defense Minister Shigeru Ishiba and LDP policy chief Hakubun Shimomura are on the fence.

"We are talking about a sitting prime minister suddenly quitting, right before the LDP leadership race. Many will think it's a great opportunity," said Naoto Nonaka, a professor of comparative politics at Gakushuin University. "It's going to be a free-for-all."

Kono, who is U.S.-educated and often considered a maverick in the old-fashioned world of Japanese politics, has long harbored ambitions of becoming prime minister and consistently places high in opinion polls asking who should take the role.

While the 58-year-old Kono is not necessarily popular within the LDP, lawmakers feeling vulnerable heading into the general election, which must be held by Nov. 28, may throw their support behind him due to his public appeal, Nonaka said.

Meanwhile, Kishida is making his second attempt at the top job after losing to Suga in the previous party presidential election last September. Having experience in diplomacy as well as key roles such as the party's policy chief, the 64-year-old has the right credentials but has been criticized as lacking the stomach to make difficult decisions.

With Suga resigning just one year after taking office, whoever succeeds him will look to avoid reverting to the "revolving door" of prime ministers changing nearly every year from 2006 to 2012.

Intraparty politics are certain to play a large role in the LDP vote, with Suga having relied on support from major factions controlled by heavyweights including former Prime Minister Shinzo Abe, Finance Minister Taro Aso and Toshihiro Nikai, the party's influential secretary general.

All of the contenders will need the backing of lawmakers outside their core groups. Kishida leads his own medium-sized faction while Kono belongs to Aso's. The 60-year-old Takaichi currently does not belong to a faction.

LDP members will be especially careful of who to choose to lead them in the general election after Suga saw his popularity plunge as COVID-19 cases surged despite progress in vaccinating the population.

The prime minister was often criticized for failing to get his message across as the public grew increasingly frustrated with living under pandemic restrictions. The government decided to go ahead with the Tokyo Olympics despite the public divided on the games amid another surge in virus infections. A record medal haul for Japan did little to move sentiment in his favor.

A nationwide survey conducted by Kyodo News last month showed the approval rating for Suga's Cabinet at 31.8 percent, down from 66.4 percent immediately after he took office last September.

"Some media outlets had it at below 30 percent, which is the danger zone for a government," said Masahiro Iwasaki, a professor of Japanese politics at Nihon University. "Collapse was only a matter of time."

The final straw was Suga's suggestions of hastily dissolving the House of Representatives and reshuffling LDP executives ahead of the party vote, a move some saw as disregarding long-established norms in a blatant attempt to cling to power.

The current four-year terms of members of the powerful lower chamber of parliament end on Oct. 21.

The LDP, which holds 276 of 465 seats, had been expected to lose a significant chunk with the unpopular Suga at the helm. Junior coalition partner Komeito has 29, while the largest opposition force, the Constitutional Democratic Party of Japan, holds 113.

The ruling coalition will almost certainly maintain its majority with a new LDP leader, though the party would likely still lose a fair number of seats, maybe around 30, if opposition parties can manage to coordinate their election strategies, Nonaka said.

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