You can't cancel an election. People have poured millions into the campaigns from donors, political parties, the networks (for the debates), not to mention the thousands of man hours that went into putting it all together and making it happen... No one in the world has the power to stop the election, not even obama.
The only thing I can think of that might cause it to be postponed is if a nuclear bomb goes off or the US gets hit by a large comet..or if Russia or some other world superpower suddenly declares war on the US (and Russia is not about to declare war despite their warning about Syria). I think if someone did declare war, obama would move the election to an earlier date so he can get the heck out of there..
The only thing I can think of that might cause it to be postponed is if a nuclear bomb goes off or the US gets hit by a large comet..or if Russia or some other world superpower suddenly declares war on the US (and Russia is not about to declare war despite their warning about Syria). I think if someone did declare war, obama would move the election to an earlier date so he can get the heck out of there..