Reprinted from Robert Reich Blog
1. Cruz is more fanatical. Sure, Trump is a bully and bigot, but he doesn't hew to any sharp ideological line. Cruz is a fierce ideologue: He denies the existence of man-made climate change, rejects same-sex marriage, wants to abolish the Internal Revenue Service, believes the 2nd amendment guarantees everyone a right to guns. He doesn't believe in a constitutional divide between church and state, favors the death penalty, rejects immigration reform, demands the repeal of Obamacare, and takes a strict "originalist" view of the meaning of the Constitution.
2. Cruz is a true believer. Trump has no firm principles except making money, getting attention, and gaining power. But Cruz has spent much of his life embracing radical right economic and political views.
3. Cruz is more disciplined and strategic. Trump is all over the place, often winging it, saying whatever pops into his mind. Cruz hews to a clear script and a carefully crafted strategy. He plays the long game (as he's shown in Iowa).
4. Cruz is a loner who's willing to destroy government institutions to get his way. Trump has spent his career using the federal government and making friends with big shots. Not Cruz. He has repeatedly led Republicans toward fiscal cliffs. In the Fall of 2013, his opposition to Obamacare led in a significant way to the shutdown of the federal government.
Both men would be disasters for America, but Ted Cruz would be the larger disaster.