The feud between Jeb Bush and Donald Trump reached toxic levels as the two attacked each over over foreign policy during this Tuesday's debate on CNN.:

The CNN Republican debate took an abrupt turn off the rails on Tuesday, with real-estate mogul Donald Trump launching a late-debate assault against former Florida Gov. Jeb Bush and the network that hosted the affair.

The derailment began when a CNN moderator asked Bush why he felt Trump wasn't qualified to be commander in chief.

Bush responded by pointing to Trump once quipping that he gets foreign-policy information from "the shows." The former governor suggested that Trump was actually watching cartoons.

"I won't get my information from 'the shows.' I don't know if that's Saturday morning or Sunday morning. I don't know which one," he quipped.

Trump responded by turning the tables on the network.

"I think it's very sad that CNN leads Jeb Bush, Gov. Bush, down a road by starting off virtually all of the questions: 'Mr. Trump this. Mr. Trump [that].' I think it's very sad. I think it's very sad," Trump said.

The business mogul then pounded CNN for being "very unprofessional" by focusing so much of the so-called undercard debate on his policies, especially his provocative call to temporarily bar Muslims from entering the US. [...]

Bush then jumped back into the conversation and he and Trump talked over one another. Bush lectured Trump, saying the world stage is significantly harder than the debate stage.

"Look, the simple fact is if you think this is tough and you're not being treated fairly, imagine what it's going to be like dealing with Putin or dealing with President Xi or dealing with the Islamic terrorism that exists," he said, referring to the presidents of Russia and China, respectively. "This is a tough business, to run for president."

Trump then delivered a laugh line.

"Oh, yeah. Oh, yeah, you're a tough guy, Jeb," Trump shot back. "Real tough."