Ordinarily I'd agree but I am not convinced he really wants the Presidency since he has risen so fast...I think he's determining that as he goes now...if or not he's going to carry this to the end.
When he was asked why he was running for the presidency, he answered, "To be President!"
I see no reason to presume he's a bald faced liar without any proof of that. I believe that, like all the other candidates, he thinks his ideas will help the country and that his being President will bring us back to our pre-Obama strength and fix the mess we're in.
And I think that of Perry, Gingrich, Bachmann, Santorum, and yes, even Romney.
They ALL want to be President because they think they have the best ideas. It would be a stretch to try to prove otherwise.