Voters in South Carolina, Nevada Weigh In

Democratic presidential candidate Hillary Clinton greets supporters with her husband, former President Bill Clinton, at a Nevada Democratic caucus rally in Las Vegas, Feb. 20, 2016.

Republican U.S. presidential candidate Donald Trump, center, greets supports at a victory rally in Spartanburg, S.C., Feb. 20, 2016. On stage with Trump are his daughter, Ivanka, left, and his wife, Melania, right.

Democratic presidential candidate Sen. Bernie Sanders, I-Vt., waves to voters as he leaves a caucus site, in Las Vegas, Feb. 20, 2016.

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U.S. Republican presidential candidate Marco Rubio applauds as he approaches the podium to speak to supporters at a South Carolina primary night rally in Columbia, S.C., Feb. 20, 2016.

Supporters of U.S. Republican presidential candidate Donald Trump celebrate the close of the polls as they watch election results at a rally in Spartanburg, S.C., Feb. 20, 2016.

A voter arrives to cast his ballot in the U.S. Republican presidential primary at a polling place at Dreher High School in Columbia, S.C., Feb. 20, 2016.

Gethsemani Community Center polling station employees tape voting notices predawn before the South Carolina Republican Presidential Primary voting commences at 7 a.m. in North Charleston, S.C., Feb. 20, 2016.

Hal Marshall playfully displays his commitment to voting after casting a ballot at Charleston's Burke High School in South Carolina's Republican primary, Feb. 20, 2016. Marshall says he voted for "the big guy," Donald Trump.

Polling station manager Barbara Heyward, left, congratulates Elisa Tunno for casting a vote in the Republican primary in Charleston, S.C., Feb. 20, 2016. Tunno voted for Marco Rubio after she "changed my mind two or three times."

South Carolina voters arrive to vote in the Republican presidential primary at Pine Ridge Middle School in West Columbia, S.C., Feb. 20, 2016.

Voters arrive to cast their ballots in the U.S. Republican presidential primary at a polling station at Dreher High School in Columbia, S.C., Feb. 20, 2016.