If there was absolutely 0 popular vote, the electoral college votes (583 of them) who are pledged to the candidate that wins would just vote for who they felt like. Since all states except for Maine and Nebraska are all or nothing,
So states like Texas which is worth 38 would lean for trump
And states like California which is 55 would vote for hillary
Whoever is the first to 270 wins so... tally up all the likely leaning right states, and then tally up all the likely leaning left states and see which ones have the most votes.