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LOUISVILLE, KY - MARCH, 1:   Republican presidential candidate Donald Trump waves to the crowd after a rally March 1, 2016 in Louisville, Kentucky. Trump is campaigning nationwide on Super Tuesday, the single largest primary voting day. (Photo by Aaron P. Bernstein/Getty Images)
LOUISVILLE, KY - MARCH, 1:   Republican presidential candidate Donald Trump waves to the crowd after a rally March 1, 2016 in Louisville, Kentucky. Trump is campaigning nationwide on Super Tuesday, the single largest primary voting day. (Photo by Aaron P. Bernstein/Getty Images)

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    GOP officials' last-ditch effort to stall Trump

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GOP officials' last-ditch effort to stall Trump

As Donald Trump continues to notch wins, Republicans including Mitt Romney step up to try to bring him down. CNN Politics Reporter Sara Murray reports

GOP officials' last-ditch effort to stall Trump

As Donald Trump continues to notch wins, Republicans including Mitt Romney step up to try to bring him down. CNN Politics Reporter Sara Murray reports