Jeb Bush speaks to an audience of voters on Feb. 18 in Columbia, S.C. Bush dropped out of the GOP presidential race two days later, after finishing a distant fourth in the state's primary. Spencer Platt/Getty Images hide caption

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Republican presidential candidates at the final GOP before the South Carolina primary on Saturday at the Peace Center in Greenville, S.C. Spencer Platt/Getty Images hide caption

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Bernie Sanders and Donald Trump deliver victory speeches at their respective watch parties in New Hampshire. Jewel Samad/AFP; Joe Raedle/Getty Images hide caption

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Republican Chris Christie of New Jersey has invested nearly his entire campaign on New Hampshire. A poor result will almost certainly effectively end his candidacy. Robert F. Bukaty/AP hide caption

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Former first lady Barbara Bush, mother of Republican presidential candidate Jeb Bush, campaigns with her son at a town hall meeting at West Running Brook Middle School in Derry, N.H. Jacquelyn Martin/AP hide caption

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Barbara Bush jokes with her son, Republican presidential candidate Jeb Bush, while introducing him at a town hall meeting in Derry, N.H. Jacquelyn Martin/AP hide caption

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Barbara Bush Hits The Trail For Son Jeb Bush
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Jeb Bush holds a campaign town hall meeting at the Alpine Club on Monday in Manchester, N.H. Chip Somodevilla/Getty Images hide caption

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Heading Into New Hampshire, GOP 'Front-Runners' Are Anything But
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Republican presidential candidate Sen. Marco Rubio, R-Fla. holds a rifle during a campaign stop Jan. 15, 2016, at Sturm, Ruger & Co., in Newport, N.H. Matt Rourke/AP hide caption

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Establishment Republicans Scramble To Top Trump
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