Obama's nuke fest seems to have gone off with more a whimper than a bang, which perhaps we should be thankful for in a certain sense, but the whole exercise was, like the Copenhagen climate meeting, a poorly run show that accomplished little of what it set out to do.
It seems proper to blame the diplomats for insufficient or incompetent preparation. Clinton's record in that regard so far is abysmal, but such is the disarray in US policies it's unfair to single her out. Besides, the DoD is now in charge of all the important diplomatic missions these days anyway.
Obama is another story. The snub by Netanyahu was entirely predictable, using the affair to pressure China (though the press) on Iran was ill conceived, and it was left up to poor Ukraine to give the only 'breakthrough of the party.
The failure seems to have now provoked or been a part of another spate of saber rattling versus Iran, including an explicit listing of Iran and N. Korea as possible nuclear targets. Since these noises have been frequent in the past, it's easy to be too sanguine about them. We can hope that while Obama is weak and fairly incompetent, he is not crazy. But that, of course, has as of yet not been proven.