One of the major tactical blunders conservatives have made is focusing on individual politicians rather than on ideas. This seems to have started with Clinton (maybe because by then the Cold War was over and that had defined much of their platform?). When Clinton took office, the primary criticisms we heard from conservatives related to his personal life; his eating habits, his marital pitfalls, etc. Very, very little discussion of his actual policies. The conservatism "opposition" to Clinton was more like a roast than a movement.
That's the problem. When you make the opposition all about individual politicians, what happens when that politician leaves? The foundation of your movement is suddenly gone. It is like the difference between spending and investing. While conservatives have been spending political capital focusing on the short term quirks of individual politicians, Democrats have been investing in the long term by making their opposition mostly about ideas that transcend individual politicians (climate change, "affordable healthcare,").
Yes, when Bush II was in office, there was plenty of focus on his accent, his speech pattern, his wild youth. But there was also constant discussion of his tax policies, social policies, and towards the end, his warmongering. Contrast that with the conservative obsession with Obama's birth certificate and alleged allegiance to Islam. Even the bashing of Obamacare largely came down to the idea-free slogan: "Obama's a socialist!"
The conservative focus on individual politicians isn't isolated to individual Democrats. They make their own campaigns about individual Republicans. Every campaign speech from a conservative mentions "Reagan Republicanism." No discussion of anything Reagan did; just a constant repetition of his name. Again, this is totally ineffective. An 18-year-old potential Republican voter doesn't care about Reagan. He could be made to care about a Reagan-related conservative idea...if one were actually presented to him.
In order to win a War of Ideas, you have to have some actual ideas. The closest thing Republicans have had to an idea is the War on Terror. And as voters have tired of it, all Republicans have done is double down (especially in '08).
Once more: climate change is a spreadable idea. Obsessing about Al Gore's personal carbon footprint isn't.