In Nate Silver's Silver Bulletin presidential forecast model, he calculates the chance for each state of tipping the election, or in other words being the 'tipping point state'.

As of market publication, Pennsylvania has a significant lead at a 33% chance of being the tipping point state over Wisconsin and Michigan at 14% each. This matches the media consensus that Pennsylvania is the most important state. However, this is calculated daily based off probabilities (not vibes!) and could change if state polling shifts appropriately.

If Pennsylvania is no longer the most likely tipping point state in any Silver Bulletin update between market start and Election Day, this market will close early and resolve to NO. If Pennsylvania is still the most likely tipping point state in the final Silver Bulletin update on Election Day, this market will resolve to YES.

I am a subscriber to Silver Bulletin and will be checking frequently to confirm any movement, but it is also likely that Nate will tweet or publish an article if Pennsylvania falls out of favour as it would be significant news. If this market is popular, I will also post occasional updates of the tipping point state probabilities.