When Prime Minister Fumio Kishida of Japan stepped down on Wednesday, he became the latest in a growing line of unpopular leaders to cycle through a sclerotic political system that has faced growing frustration from the public.

Mr. Kishida, 67, announced at a news conference that he would not run in the governing Liberal Democratic Party’s leadership contest in September, the winner of which will go on to become the prime minister.

The Liberal Democrats have held an iron grip on Parliament for all but four years since 1955. But decades of scandals and its inability to tackle many of Japan’s deep-rooted challenges have spurred widespread voter dissatisfaction.

Mr. Kishida, a moderate party stalwart, was not popular even when he first took office in October 2021, and in recent months his approval ratings have plummeted to new lows.

But for all that, even though polls have revealed the Japanese public’s deep discontent with the governing party, it only rarely appears at the ballot box. Low voter turnout and weak political opposition in Japan have left the Liberal Democratic Party largely insulated from the pressure of Potentially losing a general election.

Mr. Kishida said on Wednesday that he hoped his decision would enable the Liberal Democrats to make a big change.