We model, in a market-based democracy, different constituencies that disagree regarding the likelihood of economic disasters. Costly public policy initiatives to reduce or eliminate disasters are assessed relative to private alternatives presented by financial markets. Demand for such public policies falls as much as 40% with disagreement, and crowding out by private insurance drives most of the reduction. As support for disaster-reducing policy jumps in periods of disasters, costly policies may be adopted only after disasters occur. In some scenarios constituencies may even demand policies oriented at increasing disaster risk if these policies introduce speculative opportunities. Received September 25, 2017; Editorial decision September 3, 2018 by Editor: Thierry Foucault

When investors disagree, speculation between them alters equilibrium prices in financial markets. Because managers maximize firm value given financial market prices, disagreement alters firms' value-maximizing investment policies. Disagreement therefore impacts aggregate investment, consumption, and output. In a production economy with recursive preferences and disasters, we demonstrate that static disagreement among investors generates dynamic aggregate investment that is positively correlated with capital shocks, leading to stochastic volatility in aggregate consumption, investment, and equity returns. The direction of these effects is consistent with business cycle facts, and with several features of the 2008 financial crisis.