Here's how it broke down along party lines for voters in 2012: 38% of voters were Democrats, 32% were Republicans, and 29% were independents. Obama won with almost all the Democrats and 45% of the Independents. Assuming those numbers are somewhat consistent, all Clinton has to do is much the same. Trump has to get a much higher percentage of Independents than Clinton to win (over 60% of the Independents who don't vote 3rd Party). Complicating that is that I expect a much higher percentage of Independents to go for 3rd Party candidates this time around (it was about 5% of them in 2012, I wouldn't be surprised if it's triple that this time around).
I'm not anti-Christian. I'm anti-stupid.