While diplomats are supposed to zealously protect their nation’s interests, successful statecraft nevertheless draws lines.

Xue Jian, China’s consul general in Osaka, crossed those lines in his remarks about Japanese Prime Minister Sanae Takaichi. Even if the sentiment was genuine, his comments were both offensive and in bad taste. Absent an apology from the Chinese government, Xue should be declared persona non grata and returned to China. His is not the behavior of a diplomat.

Xue was responding to comments by Takaichi, who last week told a Lower House budget committee that a Taiwan contingency could constitute an “existential crisis” that would oblige the Japanese government to exercise its right of collective self-defense.