Photo/Illutration Prime Minister Shigeru Ishiba speaks with reporters. (Takeshi Iwashita)

Prime Minister Shigeru Ishiba faces mounting pressure to resign following his Liberal Democratic Partys disastrous showing in the Upper House election.

On July 25, Hiroyoshi Sasagawa, a senior farm vice minister, told reporters that his group of younger lawmakers had acquired enough signatures for a petition to request a joint plenary meeting of members from the two Diet chambers.

A joint plenary meeting is second only to the party convention in having the authority to make important party decisions, especially those of a pressing nature that cannot wait for a convention to be held.

A decision to submit the petition to party executives will be made after the less informal meeting scheduled July 28 that will involve LDP Diet members and at which Ishiba will be called on to explain his future course of action.

Party rules state that a joint plenary meeting must be held within seven days if more than one-third of LDP Diet members ask for one. In the present circumstances, the signatures of about 100 Diet members are needed to fulfill that requirement.

In the interim, doubts were raised about whether the petition is binding because any decision to hold a joint plenary meeting ultimately lies with LDP executives.

Other party organs are also applying pressure on Ishiba, 68, to step down.

On July 25, the LDP Youth Division submitted a request to Secretary-General Hiroshi Moriyama calling on party executives to take responsibility after an evaluation is made of the Upper House election results.

When asked by reporters, Youth Division Director Yasutaka Nakasone, 43, said the request amounted to a call for Ishiba to step down.

But for his part, Ishiba remains defiant.

At a speech on July 25 in Karuizawa, Nagano Prefecture, at the summer forum of Keidanren (Japan Business Federation) Ishiba said, “I want to manage state affairs with an even greater sense of responsibility to leave behind a better Japan for future generations.”

Earlier that day, Ishiba met with opposition party leaders to explain the agreement reached with the United States on reciprocal tariffs and he reiterated that he had no intention of resigning.