The election isn't over yet but Trump has a very high chance of winning (I threw up in my mouth a little as I wrote that). Heres a list of people and things who paved the way for it. Feel free to add!
  1. Racists
  2. White supremacists
  3. Misogynists
  4. Actual trump supporters
  5. A corrupt two party system
  6. People who didn't take his candidacy seriously
  7. Voter suppression
  8. Voter intimidation