Japanese Prime Minister Shigeru Ishiba pushed back against Trump's agenda of levying higher tariffs on imported goods, arguing it would hurt economic growth. The Japanese leader specifically called Trump ahead of the summit to confirm their plans to talk on the sidelines, which is a greater focus for Japan than the summit itself.

With both summits ahead, European leaders will have two opportunities to convince Trump about the importance of aiding Ukraine and ensuring European security.

Trump has often been a disruptor at global gatherings, badgering U.S. allies and competitors alike. But the dynamic could be different in 2025.