As the campaign went on, Walker made error after error, all based in the fact that he wasn’t well versed in national issues. When he took multiple positions on the question of birthright citizenship — again, not the biggest issue in the world but the kind of thing that can pop up in a campaign — it was clear he hadn’t really thought about it very much.
The hard lesson for Walker is that campaigns expose a candidate’s weaknesses and gaps in knowledge. While it is possible for candidates to improve as performers — they do it all the time — it is really hard for them to learn much new during the campaign. The action is simply too frantic, too non-stop for a candidate to really delve into anything.