You comment on how fresh and smart Rubio seems now. I agree. But I also recall, as you may also, Dan Quayle. In the months leading up to GHW Bush’s nomination, Indiana Senator Quayle was making the rounds as a bright, very well spoken fresh voice of conservatism. He was a former journalist, ran a family owned newspaper, etc. Seemed like a great choice for VP. Then when it happened, the roof fell in. Basically media Palinized him. Asked him the most inane questions which caught him off guard and bewildered him. He lacked preparaton and handlers. I think his relentless vetting started the second he stepped out of that mobile trailer where he met with Bush outside convention hall. Now he is a remembered as a joke and a mistake. [Oh, if only O was treated thusly by media]
Rubio has paid a lot of dues. He's no rookie.
Plus this guy is as Reaganesque as you can get. Add in fearless and you have a formidable candidate.