'That's the argument of a 5-year-old': Anderson Cooper grills Trump over attacks on Heidi Cruz
Anderson Cooper questions Donald Trump during a town hall on March 29, 2016. (Media Matters)

CNN host Anderson Cooper scolded Donald Trump on Tuesday after the Republican presidential candidate tried to pass the blame for his attacks on Sen. Ted Cruz's wife.

"After saying you were going to spill the beans about Heidi Cruz, you retweeted an unflattering picture of her next to a picture of your wife," Cooper said in reference to Trump spreading an unflattering picture of Heidi Cruz online set side-by-side with one depicting Melania Trump more favorably.

"I thought it was a nice picture of Heidi. I thought it was fine," Trump replied, prompting Cooper to say, "Come on."

"I thought it was fine," Trump insisted. "She's a pretty woman."

"You're running for president of the United States," Cooper said.

"Excuse me. I didn't start it," Trump said.

"Sir, with all due respect, that's the argument of a 5-year-old," Cooper shot back. "The argument of a 5-year-old is he started it."

Trump tried to argue that Cooper's viewpoint was "the problem with our country," but Cooper cut him off.

"Every parent knows a kid who says, 'He started it,'" the host said.

Trump then accused Cruz of sending the picture. When Cooper noted that it was actually the work of an anti-Trump super PAC, Trump then blamed "[Mitt] Romney people."

"Romney is embarrassed that he did so badly four years ago," Trump ranted. "The guy choked like a dog."

"Do you have proof he sent it out?" Cooper asked.

"Everybody knows he sent it out," Trump responded. "He knew the people in the super PAC."

Watch the exchange, as posted by Media Matters, below.