Dhaka, June 1 -- Diplomacy often unfolds behind closed doors. But occasionally, world politics is expressed more powerfully through symbolism than agreements. The recent visits of Donald Trump and Vladimir Putin belong to that category.

Taken individually, neither visit appears revolutionary. No dramatic treaties were signed. No geopolitical earthquake followed. Yet together they produced an image that may outlast any communique: the leaders of two competing powers arriving in Beijing in succession to engage China.

That image alone deserves attention.

For more than three decades following the collapse of the Soviet Union, the international system functioned under overwhelming American influence. Washington shaped security structures, d...