This paper offers a unified explanation for the slowdown of productivity growth, the decline in business dynamism, and the rise of market power. Using a quantitative framework, I show that the rise of intangible inputs, such as software, can explain these trends. Intangibles reduce marginal costs and raise fixed costs, which gives firms with high-intangible adoption a competitive advantage, in turn deterring other firms from entering. I structurally estimate the model on French and US micro data. After initially boosting productivity, the rise of intangibles causes a decline in productivity growth, consistent with the empirical trends observed since the mid-1990s.

Does UN peacekeeping promote democracy in countries wracked by civil war? Existing studies are limited and reach contradictory conclusions. We develop a theory to explain how peacekeepers can help overcome obstacles to democratization in conflict-affected countries, then test our theory by combining three original datasets on UN mandates, personnel, and activities covering all UN missions in Africa since the end of the Cold War. Using fixed effects and instrumental variables estimators, we show that UN missions with democracy promotion mandates are strongly positively correlated with the quality of democracy in host countries but that the magnitude of the relationship is larger for civilian than for uniformed personnel, stronger when peacekeepers engage rather than bypass host governments when implementing reforms, driven in particular by UN election administration and oversight, and more robust during periods of peace than during periods of civil war.