The resignation of a key aide has plunged Shinzo Abe deeper into trouble, leaving the hawkish Japanese prime minister's own future in doubt ahead of a key election, analysts said.
Fumio Kyuma resigned as defense minister on Tuesday after angering atomic bomb survivors by saying the 1945 nuclear attacks on his country by the US which killed more than 200,000 people "couldn't be helped."
While memories of the bombings are fading rapidly, especially among the younger generation, the row showed that the emotional wounds still run deep, particularly among survivors in Hiroshima and Nagasaki.
The incident has thrown fresh doubt on how long Abe can stay in office. Even before the latest row erupted, polls were showing his ruling Liberal Democratic Party (LDP) heading towards a drubbing in the July 29 upper house elections.
"The focus has now turned to how bad a loss the ruling coalition will suffer in the election, or how effectively it can do damage control," said Tetsuro Kato, a professor of politics at Hitotsubashi University in Tokyo.
"The Abe administration has been further driven into a tight corner, having already lost people's trust, particularly after it admitted problems with pensions," Kato said.
Abe's poll ratings nosedived after a government agency admitted it misplaced millions of pension payment records, a sensitive issue in the rapidly ageing country.
Abe, Japan's first prime minster born after World War II, has made rewriting the pacifist Constitution one of his major goals as part of his drive for a more assertive Japan.
But polls suggest voters care more about domestic issues such as pensions.
"People are concerned about the poorly managed public pension system," said Takashi Kato, professor of politics at Seikei University in Tokyo, who believes that Abe "should be held responsible for Kyuma's resignation."
The Japanese prime minister has been criticized for initially defending Kyuma, leaving him open to accusations from opposition lawmakers that he is too concerned about trying not to offend his key ally the US.
"Abe should have sacked Kyuma, rather than accepting his resignation offer, which gave an impression that Abe tried to avoid taking responsibility," said Yoshikazu Sakamoto, honorary professor of politics at the University of Tokyo.
The latest reverse for Abe comes about a month after the suicide of his farm minister Toshikatsu Matsuoka, a longtime ally who was accused of misuse of political funds and links to a scandal over rigged contracts.
The July 29 election is for the upper house of parliament and a defeat would not automatically cost Abe his job, as the LDP-led coalition enjoys an overwhelming majority in the more powerful lower house.
"But if the coalition suffers a big defeat, his office would be under threat," Kato said.
Potential successors to Abe include Foreign Minister Taro Aso, who lost out in last year's race for the leadership of the LDP and with it the chance to succeed the widely popular Junichiro Koizumi.
Abe enjoyed strong support after taking office last year thanks in part to early summits with China and South Korea to repair relations frayed by Koizumi's visits to a controversial war shrine in Tokyo.
His support has since fallen to an all-time low of 28 percent, with the disapproval rating topping 50 percent, according to some recent polls.