The most counterintuitive feature of the global financial system is that American problems become everyone else's emergencies, while everyone else's problems somehow benefit America. This asymmetry has a name, coined by Santiago Capital's Brent Johnson: the dollar milkshake theory. The metaphor is crude but clarifying. The United States sits at the center of the global financial system with the longest straw, and when liquidity tightens, it sucks capital out of every other economy first.

The theory rests on a structural reality that most economic commentary ignores. The world has accumulated roughly $13 trillion in dollar-denominated debt outside the United States. When the Federal Reserve raises rates, servicing that debt becomes more expensive precisely as the dollar strengthens, creating a vicious spiral. Emerging market central banks must choose between defending their currencies by raising rates into a slowdown or letting them collapse and watching inflation explode. Neither option is good. The dollar, meanwhile, keeps rising because it remains the only game in town for serious capital seeking safety.

Why the straw keeps getting longer

The dollar's dominance is self-reinforcing in ways that frustrate its critics. Despite decades of predictions about dedollarization, the greenback's share of global reserves has remained remarkably stable. The euro was supposed to provide an alternative; instead, the eurozone's structural contradictions made it a source of crises rather than a haven from them. The renminbi was supposed to rise with China's economy; instead, capital controls and political opacity keep it marginal in global finance. Every time an alternative stumbles, more debt gets denominated in dollars, which makes the next tightening cycle more powerful.

The mechanism works through what economists call a doom loop. A country with dollar debts sees its currency weaken when the Fed tightens. The weaker currency makes the dollar debts more expensive in local terms. The increased debt burden damages the economy, which weakens the currency further. Argentina, Turkey, and Sri Lanka have all demonstrated this dynamic in recent years. The pattern is predictable, yet countries keep borrowing in dollars because the rates are lower — until suddenly they are not.

The milkshake in action

The theory gained credibility during the tightening cycle that began in 2022. As the Federal Reserve raised rates at the fastest pace in decades, the dollar index surged to twenty-year highs. The British pound briefly approached parity. The Japanese yen fell to levels not seen since the 1990s. Emerging market currencies cratered. Capital flowed into dollar assets not because the American economy was healthy — inflation was running at forty-year highs — but because everywhere else looked worse.

This is the theory's most uncomfortable implication. The dollar can strengthen even when America is in trouble, because global capital has nowhere else to go at scale. Treasury markets remain the deepest and most liquid in the world. The Federal Reserve, for all its missteps, operates with more transparency than any other major central bank. American property rights, while imperfect, remain more reliable than the alternatives. In a crisis, these features matter more than economic fundamentals.

The endgame question

Johnson's original formulation suggested the dollar would keep strengthening until something breaks — either the global financial system restructures around a new reserve currency, or the United States itself buckles under the weight of its own debt and deficits. Neither outcome is imminent, but both are possible on a long enough timeline. The more interesting question is what happens in between.

The milkshake theory implies that American policymakers have more room to maneuver than their counterparts elsewhere, but not infinite room. Eventually, the debt service on federal borrowing becomes constraining. Eventually, the political will to maintain the institutions that make the dollar attractive erodes. Eventually, some alternative emerges that is good enough for large pools of capital. The theory does not predict when eventually arrives.

Our take

The dollar milkshake theory is not a prediction so much as a description of plumbing. It explains why emerging market crises cluster around Fed tightening cycles, why the dollar rallies during global stress, and why dedollarization proceeds so slowly despite widespread desire for it. The framework does not tell you when to buy or sell anything. What it does is clarify the stakes: in a dollar-centric system, American monetary policy is everyone's monetary policy, whether they voted for it or not. That arrangement has survived every challenge so far. The question is whether survival constitutes stability or merely deferred reckoning.