Here's one easy way the Republican primaries could go.
Let's say you've got your saggy Scott Brown, your Rand Paul, maybe your Ted Cruz on the outside… and then up front, your Marco Rubio and your Jeb Bush. I just can't take Mike Huckabee seriously, even though he's polling first right now. (In this hypothetical universe, it's, predictably, all men: Everyone decides Nikki Haley is too young, Mary Fallin never gets any steam, and Sarah Palin sticks her head out and everyone's checkbooks retreat in terror and she goes away again.)
How LOL is this?
Jeb is the money leader early out, just because a Bush raises money like a cat hunts a mouse. The machinery is oiled. And all the "negative perceptions" of a Bush only exist in a Libertarian or liberal mind. "Four more years of Bush" is soothing to everyone else, for some unknowable reason.
There's a brief period where Jeb is the front runner, through Iowa, New Hampshire, South Carolina, and Nevada. Let's say he loses New Hampshire (the kind of state where they get their back up about legacy names). The Republicans are compressing the primary season because it's brutal, expensive and bad for party unity. Totally reasonable, honestly. But it means zooming towards their convention, in some city that starts with a C (Cleveland, Cincinnati, Columbus) or maybe a D (Denver, Dallas) in late June or early July, instead of stupid old August. They need the time on the ground to work against Clinton. Haha, and everyone is losing their minds, because we're about to have a Clinton versus Bush race, which is hysterical, it's like a referendum on America itself. Madness!
So then there's probably a reduced Super Tuesday on March 6th, a likely not very impressive Tuesday (2012's super Tuesday had ten states). And right before that, let's say March 5th… Obama drops the hammer and says something really nice about Jeb Bush, and blammo, even though Obama's approval rate is like 8% by then, he's still Obama, and it's over, Republicans run screaming from Obama's semi-endorsement of Jeb and the Republicans are left with whoever's standing, with only three months or so for the rest of the primaries before the convention. Maybe it's Marco Rubio! Maybe it's stupid old Mike Huckabee! Maybe it's… Marsha Blackburn???
In any event, it's someone who'll lose to Hillary Clinton, who'll have extra power because Bill Clinton dies late in the summer of 2015, earning her the devotion of like 95% of all women voters. Sorry, don't get upset, he's had a rich life!