CNN anchor Anderson Cooper sparred with Donald TrumpDonald John TrumpKoch-backed group launches six-figure ad buy against Heitkamp Anti-abortion Dem wins primary fight Lipinski holds slim lead in tough Illinois primary fight MORE at a Tuesday town hall over an unflattering image he retweeted of Heidi Cruz last week. 

Cooper told Trump he had the argument of a 5-year-old when the Republican presidential candidate tried to defend his reposting the image that compared Ted CruzRafael (Ted) Edward CruzCruz says Cambridge Analytica assured him its practices were legal Dem battling Cruz in Texas: ‘I can understand how people think this is crazy’ Overnight Tech: Facebook faces crisis over Cambridge Analytica data | Lawmakers demand answers | What to watch for next | Day one of AT&T's merger trial | Self-driving Uber car kills pedestrian MORE’s wife to Melania Trump. 

“I thought it was a nice picture of Heidi. I thought it was fine,” Trump said. 

“C’mon,” Cooper responded. 

“I thought it was fine. She’s a pretty woman,” Trump fired back. 

“You’re running for president of the United States,” Cooper said. 

“I didn’t start it. I didn’t start it,” Trump responded. 

“Sir, with all due respect, that’s the argument of a 5-year-old,” Cooper said. 

“I didn’t start it. No it’s not,” Trump said. 

Trump and Cruz have been feuding since last week, attacking each other for bringing their families into the political campaign. 

Later in the town hall, when asked by Cooper about the last time he apologized for something, Trump paused and said he had to think. 

He said he apologized to his mother for using foul language and to his wife for not being presidential enough.
"My biggest problems are repeats and retweets," Trump joked. Cooper said perhaps he should learn from his past and stop retweeting.