The unfulfilled promise of public health: déjà vu all over again.

Many complain about public health's weak infrastructure and poor capacity to respond to threats of bioterrorism. Such complaints are but the anxiety-heightened expression of a periodic rediscovery of the deficiencies and unfulfilled promise of U.S. public health. An overview of more than two centuries suggests that where we are now with public health has been shaped by our earlier, limited, and crisis-focused responses to changing disease threats. We have failed to sustain progress in any coherent manner. If we do not wish to repeat past mistakes, we should learn lessons from the past to guide us in the future.