> President Elect Trump … predicated his unconditional acceptance of the results on his victory.

While I am no fan of the man, and have no doubt that he would fiercely have contested a loss, I don't think that it is quite as you have described it. What I remember is that he said that he would "keep you in suspense", and that he would accept the election results "if he was satisfied", never explicitly that he would only accept a victory for himself.