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Sen. Ted Cruz (R-Texas) issued a light-hearted response to Donald Trump labeling him "a bit of a maniac."

In a Fox News Sunday exclusive, Trump said he doesn't think Cruz has the temperament to be able to "get things done" as president. 

"When you look at the way he's dealt with the Senate, where he goes in there like a -- you know, frankly, like a bit of a maniac," Trump said.  "You never get things done that way ... You can't walk into the Senate and scream and call people liars and not be able to cajole and get along with people." 

Still declining to engage in a war of words with Trump, Cruz simply fired off a tweet containing a YouTube video of the popular song "Maniac" from the 1983 movie Flashdance.

Brit Hume reacted this morning on "America's Newsroom," saying that he believes Cruz's surge is "real," highlighting the Des Moines Register poll that gives the senator a 10-point lead over Trump.

Hume said Cruz is not counter-attacking against Trump because he thinks he will eventually be able to inherit Trump's supporters if Trump begins to fade. 

Watch his full analysis below.

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