The market has long treated the US dollar like a sovereign oak tree — deep-rooted, immovable, casting shade over everything beneath it. But with Stephen Miran now seated at the Fed’s table, that oak suddenly looks less like a permanent fixture and more like tinder. A new ideological fire has been lit inside the US central bank, and if it spreads, the greenback could be heading into one of those generational bear cycles that rewrite the global allocation map.Miran isn’t a household name on Wall Street. He isn’t a grizzled veteran of interbank dealing rooms or a scars-to-prove-it macro fund manager. He is, however, a Trump loyalist with sharp elbows and a fixation on one core belief: the US dollar is too strong, and its reserve-currency status has done more harm than good.To him, the “almighty US dollar” is not a crown jewel but a ball and chain — a culprit behind shuttered factories, hollowed-out communities, and the social rot that festers when wages stagnate. And now that conviction sits inside the marble halls of the Fed.Markets are right to take note. The US dollar has already shed more than 10% from its January peak, and history tells us this isn’t just noise. The greenback trades in long, sweeping arcs — decade-long bull and bear markets where once momentum shifts, it rarely reverses quickly. Like weather systems, US dollar cycles don’t drizzle; they pour.When a downtrend establishes itself, it doesn’t gently fade; it hammers through portfolios with relentless force, demanding repositioning across every asset class.For reference, think Abenomics. Japan’s bold revival plan in the 2010s leaned on a compliant central bank and government coordination, and the yen was the sacrificial lamb. Within three years it lost half its value, shocking the system but jump-starting Tokyo’s reflation push. Washington isn’t Tokyo, but if Miran’s fingerprints start guiding policy — weakening the US dollar as a national project — the template is there.The implications are profound. A weaker US dollar doesn’t just rearrange the FX scoreboard; it reorders the entire investment universe. Emerging markets, which have endured a lost decade under the thumb of a strong US dollar, suddenly get oxygen again. For years, EM managers had to compensate investors just to neutralize FX drag.With the greenback on the back foot, that burden lifts. It’s no coincidence that high-carry currencies like the Brazilian real and Mexican peso are already seeing speculative love. The carry trade, long dormant, is stretching its legs like a sprinter reacquainting with the starting blocks.And China looms in the background. A stronger yuan fix, even subtly nudged by Beijing to push internationalization of the renminbi, could accelerate this trend. The yuan doesn’t have to dethrone the US dollar; it merely has to act as an anchor that broadens the EM rally. Traders know the smell of a regime change in FX, and the aroma is starting to seep into the room.Meanwhile, U.S. assets face their own reckoning. Valuations in the S&P 500 sit at rarified altitudes, sustained by the oxygen tank of AI optimism. But unless those AI earnings materialize in a way few adoption curves ever have, the math won’t hold.Fund managers are already diversifying away from US exceptionalism, trimming Treasuries, and lifting allocations toward gold — a remarkable pivot that hints at the erosion of faith in Washington’s fiscal and monetary house. When central banks globally own more bullion than Treasuries, you know the tectonic plates are shifting.The real wildcard is Miran’s willingness to put ideas on the table that orthodox economists dismiss as “crackpot.” His musings about forcing U.S. security-dependent allies to swap short-term debt into 100-year bonds would, in any other era, be laughed off as satire. Now they sit uncomfortably close to the levers of power. Bond traders, trained to smell desperation in restructuring, will be quick to draw their own conclusions.None of this means the US dollar collapses overnight. Cycles this big move in arcs, not ticks. But with a bear now sitting at the Fed table, the compass is recalibrating. The era of US dollar supremacy as the unquestioned core of every portfolio may be drawing to a close. The great rotation that follows will not be orderly. It never is. EM desks will rediscover life.Carry traders will find a second wind. Gold will inch closer to becoming the world’s true reserve asset. And US investors, long spoiled by the gravitational pull of their own markets, may discover that the world outside is no longer priced in US dollar, but in alternatives.The oak tree isn’t gone yet. But it’s leaning. And once a giant starts to fall, everyone scrambles to get out from under the weight.