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 Maryland Gov. Martin O'Malley, Sen. Bernie Sanders, I-Vt. and Hillary Clinton at the NBC News-YouTube Democratic presidential debate at the Gaillard Center on Sunday in Charleston, S.C. Stephen B. Morton/AP hide caption

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Iranian President Hassan Rouhani presents the draft budget for the next Iranian fiscal year to the chairman of the Iranian Parliament Ali Larijani at the Iranian parliament in Tehran on Jan. 17, 2016. Anadolu Agency/Getty Images hide caption

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