Would John Edwards want the Vice-Presidency in return for playing kingmaker in the Democratic primaries? Perhaps not. After all George HW Bush is the only sitting 20th century Veep to have reached the top job absent assassination, death by natural causes* or the boss being forced from office (Nixon of course was defeated in 1960, but being Veep didn't harm him). Megan asks:
The VP slot seems to be a lot less important than it used to be. Thoughts on why this is?
The obvious answer is that the Vice-Presidency has rarely been very important but that, contra the idea that it is a graveyard post, it is probably more important now than it has ever been and, subject to certain circumstances, a better springboard for the top job than it has been before.
After all, if Al Gore hadn't been such an ass he'd have won a decisive victory in 2000. Two Vice-Presidents in a row would have become President and we'd be talking about how important the post it. And reasonably enough: thanks to Gore and Cheney it is a more influential position than it was in, say, FDR's day. The VP is now a genuinely national figure and it seems likely that all future Veeps will consent to being Quayle-esque nonentities.
However, common-sense also dictates that a sitting Veep can only hope to win the Presidency if his predecessor leaves office on a high. If the public is contented and feeling generous it may then be prepared to grant the team four more years. That being the case one might argue that the Vice-Presidency can, all other things being equal, help a candidate win a first term at the cost of decreasing the probability of the new President winning a second term since by that time our imaginary Veep-turned-President will have been in the White House for as many as 12 years. This would in turn guarantee that an opposing "time for a change" campaign has plenty of ammunition to fire, even if the country is doing quite well. If it isn't, then god help the would-be incumbent.
At some point voter fatigue sets in - something that will happen, I'm pretty sure, very quickly if Hillary were ever to become President. She could still win the Presidency but I'd bet she would be a single term President, After all, if we're to believe her campaign she's been a sort of co-President for eight years already. Who would really want eight more years? Even in the event that she were to win a second term it is hard to imagine her Veep over-coming voter exhaustion in 2016.
*Updated to satisfy pedants. Thanks Mr E.