TOKYO — In his resignation speech on Friday, Prime Minister Shinzo Abe of Japan said that the executives of his conservative political party were finalizing plans for selecting a new leader. Speculation about who that might be was swirling even before he took the podium.
Mr. Abe, who would have led the world’s third-largest economy until September 2021, had become deeply unpopular by the time he resigned. Still, the Liberal Democratic Party, which he leads, holds a firm majority in Parliament. Whoever the party chooses as its next leader — a process that could be completed in the next week or so, analysts say — will almost certainly be elected prime minister by lawmakers.
Less clear is who the person will be, and whether that person will be able to carve out a different public profile in the job. A dark horse could still emerge. Seiko Noda, a member of the House of Representatives, for example, indicated her desire to be prime minister but is considered an outlier.
Mr. Abe has so far declined to name a favorite candidate, saying that the leading ones were all “very promising.”
Emerging from Mr. Abe’s shadow will be difficult for any successor, in part because the departing prime minister spent years maneuvering his rivals into “positions where they really look small, no matter their physical dimensions,” said Michael Cucek, an assistant professor of Asian studies at Temple University, Japan Campus.
Jawaharlal Nehru, India’s founding prime minister, was once described as “a great Banyan tree under which nothing grows,” added Mr. Cucek, who specializes in Japanese politics. “And Mr. Abe has basically had the same role over the last eight years.”
Mr. Abe’s successor will face a Japanese public that is dissatisfied with the Abe administration’s handling of the coronavirus pandemic, even though the country has held its caseload to fewer than 68,000 infections and its deaths to fewer than 1,300.
He or she will also inherit a rapidly aging population and complex relationships with the world’s top two economies, China and the United States, which are themselves engaged in a bitter trade dispute.
Personalities are particularly important in global diplomacy during the Trump era because it is a time when “perception is not necessarily reality but perceptions do matter,” said Shihoko Goto, a senior associate for northeast Asia at the Wilson Center, a Washington research institute.
Ms. Goto said she was not sure if any of Mr. Abe’s most likely successors would be as skillful as he was in harnessing personal relationships with his foreign counterparts to Japan’s diplomatic advantage.
Here are some of the leading candidates to replace him:
Mr. Suga, 71, is Mr. Abe’s chief cabinet secretary and a leading candidate to replace him.
Because Mr. Suga is so close to Mr. Abe, he would be seen as inheriting both the good and bad parts of his legacy if he became prime minister, said Lully Miura, a political scientist and head of the Yamaneko Research Institute in Tokyo.
“This is the strong point of him and also his weak point,” she said, “because the public is kind of tired of the administration.”
Mr. Suga has a rags-to-riches background that plays well in politics. Born in the northern prefecture of Akita, he went to Tokyo to work in a cardboard factory after graduating from high school. He paid his way through university by working part-time jobs, including at a fish market.
Mr. Cucek said that in American terms, Mr. Suga’s current power was roughly equivalent to a White House press secretary, chief of staff and liaison with Congress all rolled into one — and that he would probably not want to become prime minister because he already wields more raw political power than Mr. Abe does.
Mr. Kishida, 63, is a former foreign minister who aspires to the top job. His father and grandfather were politicians, and he has been loyal to Mr. Abe and held several important roles in the party, including chairman of the Liberal Democratic Party’s policy research council.
The biggest factor weighing against Mr. Kishida’s candidacy may be that he lacks retail political skills.
Another could be geography. Mr. Abe and Mr. Kishida are both from the Chugoku region of Honshu, Japan’s main island, which has supplied many of the country’s previous prime ministers.
“Having yet another P.M. from the Chugoku, even if he is from a different faction, might rub folks the wrong way,” Mr. Cucek said.
Mr. Ishiba, 63, is an abrasive former defense minister who twice ran against Mr. Abe for the party leadership. The current prime minister is said to dislike Mr. Ishiba, in part because he nearly beat Mr. Abe in the party’s 2012 election.
Kazuhisa Kawakami, a law professor at Reitaku University, said that anyone taking Mr. Abe’s job would be expected to further his policy goals. Those include two signature aims that Mr. Abe failed to achieve as prime minister: revising the pacifist Constitution installed by postwar American occupiers, and securing the return of contested islands claimed by both Japan and Russia so that the two countries can sign a peace treaty to formally end World War II.
“Properly maintaining the Abe administration’s policies is a requirement, and those in a position to do so are those close to the center of power,” Mr. Kawakami said. “Ishiba is not.”
Mr. Motegi, the foreign minister, is a former economy minister who spent years executing Mr. Abe’s economic program, known as “Abenomics.”
He also negotiated the Trans-Pacific Partnership, a multicountry trade agreement, then helped Mr. Abe hold together the remaining 11 nations in a revised version after the Trump administration pulled the United States out.
If Japan’s political history is any guide, Mr. Motegi, 64, might not be an obvious choice for prime minister because he is not in Mr. Abe’s party faction.
But he is not a known rival, either, and he even golfs frequently with Mr. Abe, Mr. Cucek said. And if intraparty negotiations over the next few days become intractable, he added, Mr. Motegi could perhaps serve as a compromise candidate.
Mr. Kono, 57, is the current defense minister and former foreign minister, as well as a liberal maverick who belongs to a new generation of Japanese politicians that has been positioning itself to succeed Mr. Abe.
Mr. Kono hails from a family of politicians who have served in the Japanese Parliament for decades. He is Twitter-savvy, and recently told the monthly magazine Bungei Shunju that he had wanted to be prime minister ever since he became a lawmaker. But Mr. Cucek described him as an eccentric “lone wolf.”
Mr. Kono is seen by other Liberal Democratic Party members as someone who handles the United States well, and they would see him as useful if President Trump were to win the November presidential election, Mr. Cucek said.
“But I think the United States angle is not enough to carry him through,” he added.
Mr. Aso, 79, is a long-serving deputy prime minister and a former prime minister who could serve as a caretaker leader until 2021, when the Liberal Democratic Party is scheduled to hold its next scheduled election. But, in part because of his age, he is not viewed as a symbol of the party’s future.
Mr. Aso is a close ally of Mr. Abe, so the departing prime minister may feel an obligation to help him, the weekly magazine Sunday Mainichi reported in a recent analysis.
The Sunday Mainichi also noted that Mr. Aso was prone to gaffes. They include twice citing Nazi Germany as an example to emulate and comments last year that led critics to say he was blaming Japan’s low birthrate on women. He said that his comments had been misconstrued, but he also apologized and said that he should be more careful with his words. Some members of the Liberal Democratic Party fear he could embarrass them if he took the helm again.
Some of the reports swirling around the Diet, as Japan’s Parliament is known, have suggested that Mr. Aso ultimately may not run but would have a hand in picking Mr. Abe’s successor.
After a meeting on Friday night, Jun Matsumoto, the deputy chairman of the Diet Affairs Committee, said that Mr. Aso had told his colleagues that he was not aiming to be prime minister.
“He said he would like to support a candidate who can implement policies united with the colleague members among those who wish to run,” Mr. Matsumoto said.
Hisako Ueno reported from Toyko, and Mike Ives from Hong Kong. Ben Dooley and Motoko Rich contributed reporting from Tokyo.