HISTORICAL PARALLELS

Donald Trump 2015, and George Wallace 1968 (watch!)

http://crooksandliars.com/2016/01/rachel-maddow-compares-donald-trump-george 

Why Trump is attacking Cruz; why Cruz won't respond in kind

https://www.washingtonpost.com/blogs/plum-line/wp/2016/01/06/ted-cruz-is-refusing-to-take-trumps-chump-bait-heres-why/

"Lane" theory: https://www.washingtonpost.com/news/the-fix/wp/2016/01/06/