Thus, what would be more important is an analysis of the effects of unexpected moves in the short-term rate. Empirical studies that focus on these measures do not find evidence that either the monetary policy of the Federal Reserve or the Eurosystem suffers from a diminished leverage over long-term rates (Ehrmann (2005), Brand (2006)).
Second, even if it would be true that long-term interest rates are increasingly determined on the global capital market, this by no means renders monetary policy ineffective. One of the workhorses of international macroeconomic theory, the Mundell-Fleming model, dealt with precisely this issue some 40 years ago.