From a purely financial perspective, Japan, arguably America’s biggest ally in Asia, poses as much of a threat due to the sheer scale of its exposure to US debt. It’s officially America’s biggest international creditor, to the tune of $1.14 trillion.

Japan and the US conducted a rare coordinated yen intervention, raising volatility risks for carry trade speculators and currency markets

Japan and the U.S. confirm joint yen intervention, signaling readiness for further action to stabilize the yen’s decline.

Trump says US intervening to prop up yen as sign of friendship

..."they're gonna need a bigger boat..."