Reuters/Jim Young
Donald Trump.
Trump trailed Sen. Ted Cruz by 10 points in the poll. The real-state magnate attracted 30% support among likely voters. Cruz's support was at 40% and Ohio Gov. John Kasich was at 21%.
It's a big difference from last month's Marquette poll. When that poll was released in mid-February, Trump led Cruz by 11 points.
While Trump support has remained steady at 30%, Cruz's shot up in the new survey, doubling from 19% to 40% in just more than one month.
The Wednesday poll came after the GOP field dwindled to three remaining candidates. The Marquette Law School poll is widely respected among political observers.
Wisconsin's primary, which will be held next week, is the only GOP contest on the calendar between before New York primary on April 19. It awards 42 delegates, and many in the "Never Trump" movement view it as a final stand to stop the GOP frontrunner.
Both Cruz and Trump are campaigning aggressively to win the state. Cruz is touting his recent endorsement from Wisconsin Gov. Scott Walker, a former presidential candidate. While Trump has scheduled campaign events throughout the week in the Badger State.