US-POLITICS-CAUCUSES-PRIMARY-ELECTION-VOTE-IOWA-CAUCUS

Published February 1, 2016 at 3577 × 2380 in US-POLITICS-CAUCUSES-PRIMARY-ELECTION-VOTE-IOWA-CAUCUS
Volunteers make phone calls at the campaign field office of Democratic presidential candidate Bernie Sanders on January 31, 2016 in Fort Madison, Iowa, one day before the state's much anticipated February 1st caucus. US presidential candidates made a frenzied, final push to lock in Iowa voters on the eve of the first nominating contest of the 2016 election season. / AFP / Michael B. Thomas (Photo credit should read MICHAEL B. THOMAS/AFP/Getty Images)

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Volunteers make phone calls at the campaign field office of Democratic presidential candidate Bernie Sanders on January 31, 2016 in Fort Madison, Iowa, one day before the state’s much anticipated February 1st caucus.
US presidential candidates made a frenzied, final push to lock in Iowa voters on the eve of the first nominating contest of the 2016 election season. (MICHAEL B. THOMAS/AFP/Getty Images)

Volunteers make phone calls at the campaign field office of Democratic presidential candidate Bernie Sanders on January 31, 2016 in Fort Madison, Iowa, one day before the state’s much anticipated February 1st caucus.
US presidential candidates made a frenzied, final push to lock in Iowa voters on the eve of the first nominating contest of the 2016 election season. / AFP / Michael B. Thomas (Photo credit should read MICHAEL B. THOMAS/AFP/Getty Images)