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Republican presidential candidate Donald Trump peers out into the crowd during a campaign event at the International Air Response facility on December 16, 2015 in Mesa, Arizona.
Republican presidential candidate Donald Trump peers out into the crowd during a campaign event at the International Air Response facility on December 16, 2015 in Mesa, Arizona.

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    Donald Trump: Jeb Bush 'dumb as a rock'

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Donald Trump: Jeb Bush 'dumb as a rock'

Donald Trump badgered his favorite presidential foe, Jeb Bush, on Twitter, as CNN's Jeff Zeleny reports.

Donald Trump: Jeb Bush 'dumb as a rock'

Donald Trump badgered his favorite presidential foe, Jeb Bush, on Twitter, as CNN's Jeff Zeleny reports.