It is not yet clear how well the American system will respond, but the early signs are far from encouraging. What we’re learning is that our society might be far more brittle than we had once imagined. The virus has laid bare our greatest vulnerability: We’ve got the world’s biggest economy and the world’s strongest military, but it turns out we might have built the entire edifice upon layers and layers of unaccounted-for risk, because we forgot to assign a value to the true measure of a nation’s success — the well-being of its population.