TOKYO — Japan’s Prime Minister Shigeru Ishiba faces an increasingly uphill battle in Sunday’s upper house election, and a loss could worsen political instability at a time of daunting challenges, such as rising prices and high U.S. tariffs.

Japan's Prime Minister Shigeru Ishiba faces a critical challenge in the upper house election. A loss would deepen political instability amidst high prices and US tariff pressures. The ruling coalition's performance is crucial for Ishiba's future and Japan's policy direction,