Summary of vice-presidential campaign debate: Joe Biden goes off his meds

All I could think during the debate was, 'Can you imagine that hysteric as president?'  

A big part of the vice-presidential debate is to display behavior that allows voters to imagine what kind of president the candidate would make, if God forbid he had to take over the presidency at no notice. 

Paul Ryan, for all his youth, came across as mature -- calm, measured, in command of himself, not rattled by the banshee at his elbow.

The kindest thing I can say about Joe Biden's debate performance is that he came across as immature. But mostly he came across as mercurial to the point of mental instability.  The grinning and giggling and laughing he did during Paul Ryan's debate time was unsettling.

Maybe toward the end of the debate someone was gesturing at him to calm down; in any case he got a little quieter in his tone and stopped the weird laughter. But by then it was too late to counteract the impression he'd cemented over the course of more than an hour, which is that this is not what you want answering the White House phone at 3:00 AM.