Trade unions are typically able to convert their industrial power into political power. We show that, depending on the parameter constellation, stronger trade unions may be welfare-improving in terms of an increase in aggregate employment and output, if they successfully lobby for lower trade...

Empirical evidence suggests that high-productivity firms face stronger trade unions than low-productivity firms. Then a policy that puts all unions into a better bargaining position is no longer neutral for firm selection as in models with a uniform bargaining strength across firms. Using a...