The Mundell-Fleming Dilemma

Add the balance-of-payments curve to IS-LM, run the four canonical fiscal-monetary experiments under fixed and floating exchange rates, and choose Costaria's corner of the impossible trinity — knowing that the trilemma is not a theory but a constraint that has broken every regime that violated it. A 10-year stress run with a commodity shock at Year 4 and regional contagion at Year 7 tests the architecture.