Textual analysis as a presidential forecasting method
Declarative = weak (the sky is blue)
Cumulative = better (the sky is blue and the sun is out)
Conditional/Serial = best (if the sky is blue then the sun is out)

Bush is making the step from declarative to cumulative. Kerry is a natural serialist. You can twist history to make many points, but the more complex thinkers have the winning record.