Japanese Foreign Minister Fumio Kishida wants to leave his post in Prime Minister Shinzo Abe‘s cabinet reshuffle next month, domestic media said on Wednesday, a sign he may be planning to challenge the increasingly unpopular leader for the top job.

Support for Abe has plunged to its lowest since the prime minister returned to office in December 2012 with a promise to revive Japan’s stale economy and bolster its defences, opinion polls showed this week.

In a bid to turn the tide, Abe is considering a wholesale shakeup of his cabinet on Aug 3, replacing more than half of his 19 ministers, while retaining key ally Chief Cabinet Minister Yoshihide Suga and Finance Minister Taro Aso, Kyodo news agency said, quoting unidentified sources close to the matter.

It was not certain that the 59-year-old Kishida would refuse to stay on if Abe pressed him to do so, Kyodo added, however, quoting his aides. Reuters could not immediately reach Kishida’s
political aides for comment.

“Kishida’s exit from the cabinet would signal his desire to replace Abe and reinforce perceptions that Abe is on the ropes,” said Jeffrey Kingston, director of Asian studies at Temple University’s Japan campus.

Abe’s slump in popularity followed a historic defeat for his Liberal Democratic Party in a July 2 election for the Tokyo Metropolitan assembly at the hands of a novice party led by the capital’s popular governor, Yuriko Koike.

Abe’s ratings fell 13 points to 36 percent in a survey by the conservative Yomiuri newspaper and 5 points to 33 percent in a poll by the liberal Asahi newspaper.

Defence Minister Tomomi Inada and Justice Minister Katsutoshi Kaneda are expected to be replaced in the reshuffle after a series of missteps widely seen as contributing to the fall in support and the election defeat.

The election loss was a stinging rebuke to Abe’s administration, battered by suspicions of scandal over favoritism for a friend’s business and by the perception among many voters that he and his close aides have grown arrogant.

Abe has benefited until now from a weak opposition, super-majorities in both houses of parliament, and a shortage of challengers inside his party.

Just a few months ago, he had been considered likely to win a third three-year term as LDP president in a September 2018 party poll, setting him on course to become Japan’s
longest-serving leader.

But falling ratings have spurred potential rivals such as Kishida, considered less hawkish than Abe, to gear up for possible challenges, political insiders and experts say.