China's rise strains aging U.S.-Japan alliance

Key facts

• The U.S.-Japan alliance, established by a 1951 treaty, is facing new challenges.
• Sanae Takaichi became Japan's prime minister in October 2025, leading a multiparty political era.
• U.S. President Donald Trump visited Japan shortly after Takaichi's inauguration.
• Japan announced an increase in defense spending to 2% of GDP.
• Takaichi's administration must navigate domestic political dynamics and foster consensus in foreign relations.

The U.S.-Japan alliance, nearing its 75th anniversary, is confronting significant challenges, particularly in light of China's growing influence and evolving geopolitical dynamics. The partnership, founded on the U.S.-Japan Security Treaty signed in September 1951 by Prime Minister Shigeru Yoshida, is now under the stewardship of Prime Minister Sanae Takaichi and U.S. President Donald Trump.

Takaichi assumed office in October 2025, and her visit from President Trump shortly thereafter highlighted the alliance's importance. During Trump's visit, Takaichi announced Japan's commitment to increasing defense spending to 2% of GDP in fiscal year 2025, a move praised by Trump, who also emphasized the alliance's strength by visiting the aircraft carrier USS George Washington.

Takaichi, representing a hard-line conservative faction within Japan's Liberal Democratic Party (LDP), has expressed a desire for a "golden era" of relations with the U.S. However, her foreign policy approach is influenced by domestic political shifts. The withdrawal of Komeito from the ruling coalition following Takaichi's election as LDP president ended a 26-year alliance, marking Japan's transition to a multiparty political system. The sustainability of Takaichi's cabinet hinges on maintaining LDP unity and achieving policy consensus among ruling and opposition parties, requiring a "moderate conservative" approach for stable governance.