Trump also lacks two factors in Wisconsin that have served him well in other states: prominent local supporters and talk-radio air cover. In Arizona, for example, he had the backing of former governor Jan Brewer, Sheriff Joe Arpaio of Maricopa County, and several state legislators. In Wisconsin, the most visible elected official supporting Trump is Van Mobley, president of the board of trustees of Thiensville, a small Milwaukee suburb of 3,223 people.

As for talk radio, the environment in Wisconsin is dramatically different from what it is in other states, where Trump has enjoyed praise from hosts such as Laura Ingraham, Michael Savage, and Sean Hannity. (Savage is now threatening to withdraw his support for Trump in the wake of Trump’s attacks on Heidi Cruz, and Rush Limbaugh is often complimentary of Cruz.)

In Wisconsin, the key talk-radio hosts are hostile to Trump. Lieutenant Governor Kleefisch told me that talk-show hosts such as Sykes, Mark Belling, and Vicki McKenna “are used to making positive arguments for conservative ideas while also arguing for an electable candidate.”…

Wisconsin is also a reasonably priced state for TV advertising, and anti-Trump groups such as The Club for Growth are taking advantage of that. The Club is expected to spend some $2 million on ads in the state. Its new 30-second spot entitled “Math” argues that Cruz is the only candidate who can beat Trump. The message: “It’s time to put differences aside. To stop Trump, vote for Cruz.”