Since it became obvious in early March that Mitt Romney would be the Republican nominee, conventional wisdom had it that: 1) Romney was a weak candidate; 2) the Republicans would have a base problem; and 3) President Obama surely would win.
Over time, the first two prongs of conventional wisdom melted away. Romney delivered thoughtful speeches (at Liberty University, in Iowa), showed readiness to duke it out (on Bain Capital) and displayed deft aggressiveness (going to Solyndra). With his increasing proficiency and a series of self-inflicted wounds by the president (e.g., "Life of Perpetually Dependent Julia"), the conservative base warmed to Romney. The more negative and caustic the president became, the more Romney seemed to radiate Reagan-like cheery calmness.