Trump is the Romney of the cycle, he has the stable support. Cruz is the Gingrich, just another flavor of the month.
Also, Hillary is inevitable unless someone can explain how Bernie overcomes his problems with minorities.
If Iowa and New Hampshire go for Sanders, the polls will dramatically change in every state, and a path will be revealed.
Blacks and Latinos are rather inelastic voters, I doubt Bernie winning IA & NH is going to change many of their minds. And without minority support, the path is very difficult for Sanders to win big states like NY, CA, OH, MI, IL, FL, ect. Unless he can win white women in those states by at least 15%, he's not going to win.
