On September 15, 2008, Lehman Brothers — the fourth-largest US investment bank, 158 years old — filed for the largest bankruptcy in American history, some $600 billion in assets gone overnight. Within forty-eight hours the global money market had effectively frozen: banks would not lend to one another, even overnight, because none could tell which counterparty held the next pile of worthless mortgage paper. The crisis had been building since subprime defaults surfaced in 2007 and Bear Stearns was rescued in March 2008, but Lehman was the moment the system seized. The US Treasury and Federal Reserve, coordinating with central banks worldwide, then orchestrated the largest peacetime financial intervention in history — bailouts, guarantees, and money creation on an unprecedented scale — to prevent a global depression. They mostly succeeded. Most of what they did is still being argued about.
The crisis exposed a systemic failure in how the world's deepest credit market had been pricing risk. Mortgage-backed securities and their derivatives — instruments designed to spread and neutralize default risk by slicing it into tranches — had instead concentrated it inside the largest institutions, opaquely and with catastrophic leverage. Credit rating agencies, paid by the issuers, had stamped AAA on assets backed by loans to borrowers who could never repay. Regulators, ideologically committed to self-correcting markets, had been outmatched. The post-crisis settlement combined regulatory tightening (the Dodd-Frank Act in the US, Basel III internationally), the institutionalization of too big to fail as a working assumption — the largest banks emerged larger — and a decade of unconventional monetary policy (zero rates, quantitative easing) that kept asset prices high and wage growth low, widening the gap between owners of capital and everyone else. The political residue proved at least as consequential as the economic one. The crisis discredited the technocratic competence of the Western elite, fueled the Tea Party on the right and Occupy on the left, and laid the groundwork for the populist revolts — Brexit, Trump, the European far right — that reshaped the developed world over the following decade.
Every contemporary debate about financialization, inequality, populism, and the legitimacy of expert governance runs through 2008. The bailouts that saved the banks but not the homeowners crystallized a durable conviction that the rules are rigged — a grievance now metabolized by movements across the spectrum. The crisis is the single most consequential domestic-policy event of the early 21st century in the developed world, and we are still living inside its political consequences: low trust, high debt, and a politics organized around who got rescued and who did not.