**I agree with the visibility and prestige (and even power), but how many Secretaries of State have ascended directly to the presidency?**
How many have wished to? Which leads to we can speculate all we may like and the writer can make as many statements as he wants about Sec Rice becoming VP but does she want to or indeed want to be President in the future.
I can't speak for her. I'm only speaking for myself, and obviously quite a few other Americans. I think she'd make a damn good one.