A new poll finds Ted Cruz leading Donald Trump by one point in the critical winner-take-most, April 5 Wisconsin primary.

An earlier poll of the state in February had shown Trump with a 10 point lead. Cruz’s surge is driven by his support from a majority people who were backing Sen. Marco Rubio and Dr. Ben Carson.

The poll of 439 likely primary voters, conducted by Emerson College, shows Cruz with 36 percent support, followed closely by Trump with 35 percent. Kasich is in third with 19 percent support.

Kasich seems to be drawing support away from Trump, as Kasich’s supporters have more favorable views of Cruz than Trump.

Trump’s favorable numbers are low in Wisconsin among Republicans, generally. Views of the GOP frontrunner are roughly even with Republican men, i.e. 50 percent with a favorable view and 47 percent unfavorable. Trump, however, is 10 points underwater with Republican women (40 percent favorable, 50 percent favorable.) Trump is particularly unfavorable with Independents in the state, who can vote in the GOP primary. Over 60 percent of Independents in Wisconsin have an unfavorable view of Trump, while just 33 percent have a positive view.

Cruz, in contrast, has strong favorable ratings with Wisconsin Republicans. He is +32 among Republican men, 64-32 and +26 with Republican women, 58-32. Cruz even has a positive image with Independents in the state, 48-44.

The Emerson poll also tested hypothetical general election match-ups. The poll of 922 likely general election voters finds Donald Trump trailing both Hillary Clinton and Bernie Sanders by nine points, 38-47. Cruz and Clinton, however, are essentially tied, with Clinton leading Cruz by one point, 46-45 percent.

The winner of the statewide vote in Wisconsin is awarded 18 delegates. Another 24 delegates are awarded to the winner in each of the state’s eight Congressional Districts. The candidate who wins a Congressional District is awarded three delegates. There are no delegates awarded at the state-level or Congressional level for second or third place.

Wisconsin is the only state voting on April 5th, making it likely that all three campaigns will devote considerable time to the midwestern swing state. Kasich is certain to campaign aggressively in Wisconsin, as states in the midwest are an important part of Kasich’s campaign narrative. He hasn’t done especially well outside his home state of Ohio, but be could cut into Cruz’s support enough to tip the state to Trump.

Wisconsin Gov. Scott Walker, who abandoned his own run for the White House late last year, has not endorsed anyone in the contest. If he chooses to endorse either Cruz or Kasich, it could make a critical difference in the final stretch.

The recent endorsement of Ted Cruz by Jeb Bush, however, suggests that establishment Republicans could be moving to consolidate behind Cruz at the expense of Kasich.

Emerson College, which conducted the poll, has one of the better track-records this primary season. If anything, the poll has slightly overestimated Trump’s support. It was the closest to the results in Iowa, although it showed Trump leading the Hawkeye State by one point. It also showed Cruz leading Texas by only three points.

It came closest to estimating Trump’s final vote in New Hampshire, South Carolina, and Massachusetts. Each poll, and each state, presents its own challenges, obviously. That said, Emerson’s results so far warrant serious attention to this poll.

Since the primary voting began, there hasn’t been a two-week window between contests until now. Primary votes have occurred almost every few days throughout February and March, often faster than news of candidates dropping out could be absorbed by the electorate.

In many ways, the Wisconsin primary is the start of the Fourth Quarter of the nominating contest. It is likely to be closely contested until the clock runs out in early June.