The point about presidents is pretty hard to dispute. Cronin thinks the last reasonably successful repeat term for a president was Franklin Roosevelt's third--which I don't count because his second term was pretty lousy. You could argue that Woodrow Wilson had a decent second term, helping to win the First World War, but then he was humiliated on the League of Nations and ended his presidency pretty much in disgrace. Theodore Roosevelt was the only indisputably successful second-term president in the last century, and even he takes an asterisk because he was only elected once--his first term was a partial one forced by an assassination.
Anyway, enough about presidents. What's the story on governors? My not-too-carefully thought out instinct is that the strong governors of the last decade, at least, have tended to do as well or better in second terms than first ones. Parris Glendening got off to a terrible start in Maryland, then came around quite impressively later. Tommy Thompson in Wisconsin and John Engler in Michigan seemed to function at a pretty even level of effectiveness through careers that went into second terms and beyond. Of course, there's the fiasco of Bob Taft in Ohio, but that looks like an aberration. By and large, I think Cronin is right that the "second-term slump" common to virtually all presidents isn't much of a problem for capable governors.
Anybody have an idea why this might be the case?