This paper develops a new approach for exploring the effectiveness of foreign currency intervention. The approach focuses on long swings in real exchange rates and their associated misalignments with respect to short-, medium-, and long-run cycles in macroeconomic fundamentals for 26 advanced and emerging market economies, spanning the period 1990q1-2018q2. The evidence supports the hypothesis that central banks can lean effectively against short- misalignments of the real exchange rate from the level implied by macroeconomic fundamentals. The effectiveness of intervention rises with the size of the misalignment, and with persistent one-sided interventions, as well as sales being more effective than purchases.