That all depends.
Take Alan Keyes, for example. A great speaker...all conservatives loved the way he talked.
However, he fell apart during his Senate campaign. And for those who say, "they played dirty tricks against him" do you not think they would do the same and more if he ran for the Presidency?
You have to be more than "a real conservative". You have to have skills also.
Most times, What’s up, the ideas of a movement are more important than it’s current leader, and those ideas will survive far beyond any leader.
You are correct, though, that a great candidate would be a big help in any election.