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So that's why Trump seemingly invoked his hand size - and penis size - in a shocking moment during Thursday night's GOP debate.

But where and how did this all begin? "On all of them he has circled his hand in gold Sharpie [permanent marker] in a valiant effort to highlight the length of his fingers", Mr Carter says.

"He's always calling me 'little Marco, '" the Florida senator said. He brought up the issue in a campaign rally in Virginia on Sunday.

Despite Rubio's cover-up that the comment reflected on the candidate's trustworthiness, Trump said the implication was that "if they're small, something else must be small".

When Jones mentioned that Rubio was running against Trump in the primary, Rubio lamented that Trump's controversial candidacy was fracturing the Republican Party. He's like 6-foot-2, which is why I don't understand why he has hands the size of someone who's 5-foot-2.

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The crowd roared in approval and Rubio waited for them to quiet down and added: "You can't trust 'em!"

Mr Rubio said his rival had "mocked everybody" with personal attacks. It is well documented that Trump is strangely insecure about the size of his tubby little piggies to the extent that the journalist who first pointed them out decades ago still gets photos to this day with captions like "See?"

And then Trump assures America on live television that there's no problem with the size of his genitalia. "[Rubio] hit my hands". "I have never heard of this", Trump continued, neglecting to reveal his repeated mailings to Carter. "And you know what they say about men with small hands?".

"This guy has a number one, the number one absentee record in the United States Senate", Trump said.

"I guarantee you, there's no problem", Trump promised.