The third resignation since Japanese Prime Minister Fumio Kishida revamped his Cabinet in September has dealt a further blow to his leadership.
The departure of Kenji Kanda, senior vice finance minister, comes as the prime minister's faltering popularity is leading some in his ruling Liberal Democratic Party to question his ability to lead.
Earlier this year, Kishida was eyeing a dissolution of the House of Representatives before year-end as his government was regaining momentum.
But the latest resignation has deprived Kishida of the chance to call a snap election, pundits say.
A ruling party lawmaker said if Kishida "dares to take the risky gamble of dissolving the lower house to break the deadlock, many LDP lawmakers will attempt to oust his government as they believe that the party will lose a snap election under him."
The ruling party lawmaker said on condition of anonymity that an increasing number of LDP members believe the current government has "reached a crucial turning point."
Some LDP lawmakers have openly expressed doubt about Kishida's leadership, with the approval ratings for his Cabinet having plunged below 30 percent in some media polls, the lowest levels since it was launched in October 2021.
Hiroshige Seko, the LDP secretary general in the House of Councillors, said in a recent parliamentary session, "The biggest reason why support rates for Kishida's Cabinet have not improved" is that he "has not shown himself to be a leader."
Seko, a member of the largest faction in the LDP, asked Kishida, "Do you feel frustrated that no matter how hard you try, you are not appreciated by the people? I cannot help but sense some weakness in the prime minister's decisions and words." Seko later apologized to Kishida for his remarks.
The opposition camp has also stepped up its questioning of Kishida's ability to manage the government, with Akira Koike, head of the secretariat of the Japanese Communist Party, saying the prime minister "should step down."
Opposition parties had urged Kishida since last week to sack Kanda, threatening to boycott Diet deliberations on a supplementary budget to fund new economic steps as long as he remained in the Cabinet.
Kanda, who is also a tax accountant, resigned Monday after admitting land and property belonging to his company had been seized by authorities on four occasions between 2013 and 2022 due to the nonpayment of fixed asset taxes.
In October, Taro Yamada gave up the role of parliamentary vice education minister after it was revealed he had an extramarital affair, while Mito Kakizawa left the post of senior vice minister for justice over an alleged violation of the election law.
As Kanda served in the Finance Ministry, which is in charge of overseeing Japan's taxation, Kishida was slammed by opposition parties and voters for having appointed a tax delinquent to such a role.
Kishida has strived to prop up support rates by pitching his diplomatic achievements, including hosting the Group of Seven summit in May in Hiroshima, where his constituency is located.
Desperate to prevent his popularity from tumbling, the prime minister has recently turned his attention to the economy, but it has left an impression among the public that he is not well-versed in economic matters, analysts said.
The new economic stimulus package featuring an income tax reduction, announced in early November, has done little to revive support for Kishida, instead fueling criticism that he was making a populist gesture ahead of a lower house dissolution.
Kishida has promoted his proposed income tax cut as an effort to "return" some of the government's revenue to the public, but Finance Minister Shunichi Suzuki has said the funds have already been allocated for policy measures and debt repayment.
Some pundits have expressed skepticism about Kishida's familiarity with Japan's fiscal structure.
"Normally, when we say 'return,' we mean we will give back surplus funds," said Motohiro Sato, a professor of public finance at Hitotsubashi University. The prime minister's comments "did not capture the overall picture of public finances and have created misunderstanding" among voters.