But if the Fed has only one effective instrument – interest rates – its two goals of economic and financial stability cannot be pursued simultaneously. Either the Fed pursues the first goal by keeping rates low for longer and normalizing them very slowly, in which case a huge credit and asset bubble would emerge in due course; or the Fed focuses on preventing financial instability and increases the policy rate much faster than weak growth and high unemployment would otherwise warrant, thereby halting an already-sluggish recovery.