Jesse stopped by his neighbourhood pub for a few beers after work one day. After having consumed way too much beer, Jesse agreed to sell his 2010 BMW (worth approximately $35,000) to Jonas the bartender for $5000. Even in his drunken state Jesse was reluctant to sell his BMW for such a low price but Jonas threatened to post some very compromising pictures of Jesse on Facebook. Jonah also said that he would send copies of the pictures to Jesse's wife. Jesse made the deal.

What principles of contract law might apply to this case?