Presidential candidates make last-minute push through state before Iowa Caucus voting kicks off.
Republican presidential candidate Donald Trump, accompanied by (from second from left) wife, Melania; daughter, Ivanka; her husband, Jared Kushner; speaks during a campaign event in Waterloo, Iowa, Feb. 1, 2016.
Democratic presidential candidate Hillary Clinton takes photos with workers at her campaign office in Des Moines, Iowa, Feb. 1, 2016.
Republican presidential candidate, Sen. Ted Cruz, R-Texas, carries his daughter Caroline, 7, as he arrives at Green County Community Center for a campaign event in Jefferson, Iowa, Feb. 1, 2016.
U.S. Democratic presidential candidate Bernie Sanders speaks to reporters from his bus outside his campaign's Iowa headquarters in Des Moines, Iowa, Feb. 1, 2016.