I am not sure about this. But it seems to me that if the SCOTUS declares any of the Presidential candidates Constitutionally ineligible it would not toss the election. It would only mean the Electors could not elect that man President. In other words, determining Obama ineligible would merely free "his" Electors to elect another.
This was how the Constitution was originally written and I believe is still written. The Constitution has no provisions for political parties and binding by the States of Electors to vote for a particular candidate has always been of dubious Constitutionality (in my estimation).
Food for thought.
I remember that Hillery "suspended" her campaign.
Did she ever "end" it?
Could she be eligible to be elected by the Electors?