Personally when I book an holiday I do that well in advance (4 to 6 months) trying to get a good deal. Most of the time cancel an holiday is expensive. Back in October I was looking for a ski holiday and looked at Denver, what put me off was not the possibility of Trump or Clinton be the president but the dollar vs pound. I do believe that one main reason for the decline in this period was the strong dollar appreciation against other currencies back in Nov/Dec. For many holidays travellers, economic reasons count more then political reasons when choosing the holiday destination.

Said that I'm going next week to Chicago.