Presidential Candidates Build Momentum

Republican presidential candidate Donald Trump, is flanked by his two sons, Donald Trump Jr., left, and Eric, while speaking at a caucus night rally Tuesday, Feb. 23, 2016.

Voters line up outside a Republican caucus site, Feb. 23, 2016, in Las Vegas.

Republican presidential candidate Ben Carson speaks to reporters during a campaign stop in Las Vegas, Nevada, Feb. 23, 2016.

Democratic presidential candidate Hillary Clinton takes pictures with supporters after a campaign event at the Central Baptist Church in Columbia, S.C., Feb. 23, 2016.

U.S. Democratic presidential candidate and U.S. Senator Bernie Sanders greets audience members at a campaign rally in Norfolk, Virginia Feb. 23, 2016.

Republican presidential candidate Donald Trump gives thumbs up as he visits a caucus site, Feb. 23, 2016.

Supporters cheer during a caucus night rally for Republican presidential candidate Donald Trump, Feb. 23, 2016.

Republican presidential candidate, Sen. Marco Rubio, R-Fla., gives a thumbs up during campaign event, Feb. 23, 2016 in Kentwood, Mich.

Republican U.S. presidential candidate Ted Cruz addresses supporters at a rally after the Nevada Republican caucuses in Las Vegas, Nevada Feb. 23, 2016.