is that why he has so much heart trouble? 
to respond to the OP - what’s wrong with being presumptuous? It seems to me that Mr Obama is in a similar position that Princess Elizabeth was in, before the death of her father, King George VI. Since it was possible to imagine a scenario that would prevent her from becoming Queen, she was the heiress presumptive to the throne.
Clearly, the second. It hasn’t happened yet, and it’s possible that it won’t happen. As I said, there’s nothing that could possibly prevent Obama from being 44 once he take oath of office. If a sniper nails him at that moment, he’s still the 44th President of the US, forevermore.
That’s absurd. It’s presumptuous to talk about anything that hasn’t happened yet, because maybe it won’t happen after all? It would be presumptuous to say that on day 1, Obama will close Gitmo and stop torture, because clearly at least one of those, if not both, is going to be an extended process, and he may well not do either for a little while (though they’re clearly high on his to-do list). It’s not presumptuous to say that he will be the 44th President, because barring some extraordinary circumstance, it’s going to happen.
That’s not presumptuous by most peoples’ definition. It’s merely overwhelmingly likely.
If your criteria is simply “it’s possible that it won’t happen,” then you’re crazy. By that logic is it just as presumptuous to say that Obama won’t be 44. It’s equally presumptuous to say that the Sun won’t come up tomorrow as that the Sun *will *come up tomorrow, since both possibly might not happen. In fact, *any *belief about the future would be presumptuous by your ridiculous standard.