NEW YORK — A pointed question now hangs over global markets as the US Treasury links arms with Japan to confront yen bears: who actually holds the leverage — Washington or Tokyo? Treasury Secretary Scott Bessent plainly wants his Japanese counterpart, Finance Minister Satsuki Katayama, to treat this joint intervention as a privilege — to feel humbled, even, that President Donald Trump deems Japan worthy of American support as the yen hits 40-year lows. Trump casts the first US–Japan currency operation since 2011 as a “signal of friendship,” a gesture he claims will lift economies everywhere. And it’s true: violent yen swings can be brutally destabilizing. Few financial accelerants are more explosive than the “yen carry trade,” a strategy that has vaporized more than a few hedge funds.