Newt Gingrich on Hannity: Trump's Retweet Disparaging Heidi Cruz "Utterly Stupid"...It Sent a Signal of "Instability" To Voters

Newt blasts Trump for going down this road and getting into a ridiculous back and forth on twitter

"It has weakened everything Trump should be strengthening"

WATCH: Gingrich calls for Donald Trump to be more disciplined.