A voter casts his ballot in the Wisconsin presidential primary election at a voting station in Milwaukee on April 5, 2016.
A voter casts her ballot in the state's primary at the South Shore Park Pavilion in Milwaukee on April 5, 2016.
Republican presidential candidate Donald Trump leaves a polling place at the Waukesha Fire Department on April 5.
Trump remains the national frontrunner ahead of the Wisconsin primary, but his support among Republicans and Republican-leaners has dropped three points to 45 percent, down from 48 percent last week.
Voters cast their ballots at the South Shore Park Pavilion in Milwaukee.
Voters cast their ballots in Wauwatosa.
Guests cheer as Democratic candidate Senator Bernie Sanders speaks at a campaign rally at the Wisconsin Convention Center in Milwaukee on April 4.
Republican Candidate Senator Ted Cruz makes a campaign stop at the Mars Cheese Castle in Kenosha on April 4.
Democratic presidential candidate Senator Bernie Sanders speaks to guests at a campaign rally at the Wisconsin Convention Center in Milwaukee on April 4.
Sen. Ted Cruz (R-TX) celebrates with his wife Heidi at the American Serb Hall Banquet Center after the polls closed on Tuesday night in Milwaukee, Wis.
Supporters of Ted Cruz celebrate at his Wisconsin primary night rally in Milwaukee, Wis., on Tuesday night.
Democratic presidential candidate Sen. Bernie Sanders, I-Vt., gestures to supporters during a campaign rally in Laramie, Wyo. on Tuesday. Sanders won the Democratic presidential primary in Wisconsin.
Supporters cheer as Bernie Sanders speaks during a political rally on Tuesday in Laramie, Wyo.