“Revolving-Door” Prime Ministers?

Japanese Prime Minister Shigeru Ishiba resigned after less than a year in office, but his short tenure did not prevent him from overseeing two major electoral defeats for his Liberal Democratic Party (LDP). Ishiba explained that he delayed stepping down until Tokyo and Washington concluded tariff negotiations, adding that he felt a sense of closure after the two allies signed a memorandum on Japanese investment and U.S. President Donald Trump issued an executive order lowering duties on imported Japanese autos. 

Yet mounting pressure within the LDP also drove Ishiba’s departure. Calls for his resignation began after the ruling coalition lost its majority in the upper house election in July. The pressure intensified when LDP Secretary General Hiroshi Moriyama, one of the prime minister’s closest aides, resigned on September 2. The timing of Ishiba’s own resignation—just one day before the LDP was set to decide on an early leadership election—underscored how much his position had weakened. 

From the outset, Ishiba’s brief tenure was marked by internal criticism. He struggled to navigate the LDP’s deep divisions over the party’s long-term vision. And public frustration with the LDP, already heightened by scandals under predecessor Fumio Kishida, only grew worse after Ishiba’s own “gift voucher scandal” in March. It reinforced perceptions of an unaccountable ruling party. 

Compounding these domestic challenges was the timing of his premiership. Ishiba entered office just as Trump began his second term, complicating Japan’s foreign policy agenda. Although the prime minister’s first bilateral meeting with the president in February was widely seen as successful, trade negotiations soon soured relations. The talks dragged on for months, with Japan’s chief negotiator traveling to Washington ten times before an agreement was reached. 

Ishiba’s successor will inherit a formidable set of challenges at home and abroad. The domestic priority will be to restore public trust in the LDP. As a party that has dominated Japan’s politics since the 1950s, the LDP has little tradition of reinvention, but a fresh strategy and a more unifying leadership style are urgently needed. The next leader must not only heal internal rifts but also address voter concerns about the economy and rising prices. 

On the international stage, US-Japan relations will remain a focal point, particularly in the areas of trade and security. Navigating an unpredictable Washington will require a leader who is assertive and flexible, and able to cultivate new partnerships, such as with Europe, that are expected to become increasingly important for Japan. 

Among the leading contenders to assume this mantle are Shinjiro Koizumi and Sanae Takaichi. Koizumi, currently agriculture minister, is young but hails from a prominent political family, which could heighten perceptions that he is just another establishment candidate. He is well-versed in US politics and enjoys the backing of former Prime Minister Yoshihide Suga. Takaichi, who narrowly lost to Ishiba in last year’s leadership race, is seen as a protégé of another former prime minister, Shinzo Abe. The results of an August Nikkei poll ranked her as the candidate “best suited to be the next prime minister”. Her staunch conservative views could attract voters who recently shifted toward new right-wing parties, potentially drawing them back to the LDP. 

The leadership contest will unfold in the coming weeks. Some analysts suggest that Ishiba’s successor may call a snap election to secure a mandate, but the LDP’s steep decline in public support makes that prospect uncertain. Japan’s last five years of political turbulence have raised concerns of a return to the “revolving-door prime ministers” era of the 1990s and 2000s. Such instability risks undermining the country’s global credibility while complicating domestic policymaking. Ishiba’s resignation, therefore, marks the end of a short-lived premiership but heralds a pivotal moment for the LDP as it faces the dual challenge of renewal and leadership at a time of mounting uncertainty.