9:30 p.m. ET
Ted Cruz is the winner of the Wisconsin Republican primary, CBS News projects.
9:25 p.m. ET
According to the CBS News Wisconsin Republican primary exit poll:
Cruz is running well across many groups of Wisconsin primary voters. He is beating Trump among men and women by about 10 percent, and he is ahead of Trump in all age groups.
Trump did less well in Wisconsin among groups of voters who have been his core supporters in previous primaries.
Cruz is winning among those with college degrees and among those without. They are about even among those with no more than a high school degree.
Cruz does better among more affluent voters but still runs almost even with Trump among those with incomes under $50,000.
Cruz runs well among those who said they are "very conservative" as he has in previous primaries, but he also edges out Trump among those who said they are "somewhat conservative." Trump has generally beat Cruz among those who say they are somewhat conservative. Trump does lead Cruz among political moderates.
As many as 34 percent of Republican primary voters say that bringing needed change is the candidate quality that most mattered in their vote decision; Cruz and Trump run neck and neck among these voters. This is better than Cruz has done in previous primaries. Cruz ran well ahead of Trump among voters who said that they want a candidate who shares their values and among those who wanted a candidate who can win in November.
Sixty-five percent of Republican primary voters said they were very worried about the direction of the nation's economy, and Cruz beat Trump among these voters.
Seventy percent support a temporary ban on Muslims who are not U.S. citizens entering the country, and Cruz and Trump are very close among this group.
Trump does beat Cruz among those who want to deport illegal immigrants who are not U.S. citizens, but only about one in three Republican primary voters support this position. Cruz topped Trump easily among the majority of primary voters who want to offer illegal immigrants a chance to apply for legal status.
Trump did very well among the half of Republican primary voters who want the next president to be from outside the political establishment, but he only got 7 percent of the vote of those who prefer the next president to have political experience.
The Republican exit poll asked voters, "If no one wins a majority of the delegates before the convention, should the party nominate the candidate with the most votes in the primaries or the candidate who the delegates think would be the best nominee?"
More than half, 56 percent, said the party should nominate the candidate with the most votes. Another 42 percent said it should be the candidate who the delegates think would be the best nominee. However, this varied widely between Trump and Cruz voters. As many as 83 percent of Trump voters said the nominee should be the candidate who won the most votes in the primaries. Among Cruz supporters, 56 percent said it should be the best nominee, and 42 percent said it should be the candidate with the most votes.
9 p.m. ET
Polls have closed in Wisconsin, and CBS News projects Ted Cruz has a solid lead over Donald Trump and John Kasich.
Cruz is performing very well with evangelicals (winning 53 percent of their support, compared to Trump's 35 percent support) and those who say values is their top candidate quality. Both men and women prefer Cruz over Trump by more than 10 points.
Trump, meanwhile, is winning independents, as well as those say trade with other countries negatively impacts U.S. jobs, and those looking or an outsider.
While most voters in these states made up their minds about who to vote for a while ago, about a third decided in the last week. Cruz wins both late and earlier deciders.
Most Republican voters in Wisconsin (53 percent) say Trump has run the most unfair campaign, while 26 percent say Cruz has and 10 percent say Kasich has.
More than one third of voters scared of a Trump presidency
More Republican primary voters would be excited or optimistic if Cruz were elected president, compared to Kasich and Trump. More than half of Republican voters have negative views about a Trump presidency, including more than a third who are scared about Trump - the highest of the three candidates.
Still, most Wisconsin Republicans overall say they would support Trump or Cruz in a general election race against Hillary Clinton. But just about half of Cruz supporters would back Trump in a contest against Clinton, while four in 10 Trump supporters would back Cruz in a match-up against Clinton.
When asked directly who would have a better chance of beating Hillary Clinton, more say Cruz (44 percent), followed by Trump at 35 percent and then Kasich (17 percent).
8:23 p.m. ET
More than half of Republican primary voters in Wisconsin say trade with other countries hurts jobs in the U.S.
8 p.m. ET
Government spending, as well as the economy, are the most important issues to Republican primary voters in Wisconsin, the exit polling shows.
7:12 p.m. ET
Here's a reminder of where the candidates stood in the delegate count ahead of the Wisconsin primary, in which 42 delegates are at stake:
5:35 p.m. ET
As many as 69 percent of Republican primary voters say they support temporarily banning Muslims who are not U.S. citizens from entering the U.S.
But 63 percent say that they think most illegal immigrants working in the U.S. should be offered a chance to apply for legal status; 32 percent say they should be deported.
Meanwhile, 66 percent of Republican primary voters say they are very worried about the direction of the nation's economy.
Republicans in the exit poll were asked who they would vote for if the candidates in November were Democrat Hillary Clinton and Republican Ted Cruz, or Clinton and Donald Trump. Clinton does not draw significantly more votes from these Republican primary voters if she runs against Trump (10 percent say they would vote for her) than if she runs against Cruz (7 percent say they would vote for her).
A significant number of the primary voters would consider voting for a third party candidate if either Cruz or Trump is the Republican nominee (18 percent if the nominee is Cruz; 16 percent if it's Trump).
5:17 p.m. ET
Wisconsin Republicans are casting their ballots in the 2016 primary Tuesday, choosing from Donald Trump, Ted Cruz or John Kasich. The Wisconsin primary is the last best chance Cruz may have to blunt Trump's momentum for weeks.
Polls opened at 8 a.m. ET and will close at 9 p.m. ET.
The economy and government spending are the top issues for Republican voters in Wisconsin today, according to CBS News exit polling. As many as 31 percent named the economy, while 32 percent said government spending. Another 29 percent said it is terrorism.
In addition, 54 percent of Republican primary voters say U.S. trade with other countries takes away jobs from the U.S. Just 34 percent said it creates jobs. These views are similar to what they were in a number of other primary states.
As for the candidate qualities that matter most to Republican primary voters, 36 percent said they're looking for someone who can bring about change. Another 32 percent said they're looking for a candidate who shares their values, while 19 percent said they're looking for someone who tells it like it is. Twelve percent said they want a candidate who can win in November.
As we've seen in earlier primaries, there is a strong undercurrent of frustration with government and the party among these voters. About a third of Wisconsin Republican primary voters are angry at the federal government - similar to the percentage seen in other Midwestern states, but lower than in some southern states.
The Republican electorate is divided over whether they want the next president to be outside of politics or to have political experience. As many as 51 percent feel by they been betrayed by politicians in their own party.
When it comes to world affairs, 48 percent of Wisconsin Republican voters say the U.S. should take more active role, 29 percent say less active, and 21 percent say the same.
There are 42 delegates up for grabs in the Wisconsin GOP primary -- 18 will be awarded to the statewide winner. The other 24 are divided equally among the state's eight congressional districts; the winner of the district gets its three delegates. If Cruz wins nearly all of the delegates, it will hurt Trump more than it helps Cruz. That's because it's already nearly impossible for Cruz to win the 1,237 delegates needed to clinch the nomination outright. At the same time, if Cruz wins most of Wisconsin's delegates, Trump may never get to 1,237, either.
According to CBS News' latest count, Trump leads the GOP field with 737 delegates, Cruz has picked up 460 and Kasich has 143.
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