MILWAUKEE — Everyone knows Milwaukee County is not Donald Trump country; southeastern Wisconsin Republicans are expected to go heavily for Ted Cruz in Tuesday's GOP primary. But in case there was any confusion, the Milwaukee County Republican Party's "Wisconsin Decides 2016" event Friday night was a three-hour lesson in why Trump is having problems in the Badger State.

Cruz and John Kasich appeared at the event. Trump sent Sarah Palin as his surrogate. Kasich was introduced by former Gov. Tommy Thompson, who managed to get pretty worked up on behalf of a candidate who is a distant third in a three-man race. Cruz was introduced by Gov. Scott Walker, who won ovation after ovation before even mentioning Cruz's name. And Palin? There was no one to introduce her. County GOP chairman David Karst dutifully did the job, after explaining that the Trump campaign had asked him to.

The audience sat on its hands when Palin spoke. Taking in the scene, it was hard to remember how popular she was with Republicans eight years ago, when she was the GOP vice presidential candidate, and even four years, when some thought she might run herself. On Thursday, Palin stuck mostly to a script touting Trump's positions on trade, illegal immigration and military strength. The room was extraordinarily quiet.

Of course, it was a non-Trump crowd in a non-Trump part of the state. The audience wasn't going to enthusiastically receive Trump, or his surrogates, under any circumstances. And then Walker's reception shed some light on why Trump is having difficulty here. Specifically, it showed why Trump was ill-advised — crazy, actually — to attack Wisconsin's Republican governor. For three reasons:

1) State Republicans respect Walker tremendously. At enormous political, and sometimes personal, risk, Walker's Act 10 budget reform broke the back of the hugely powerful Democratic public-sector unions in Wisconsin. In the process, Walker became the target of the entire Democratic power structure — organized labor, office holders (up to the president himself) activist groups, big donors. They threw everything they had at Walker, first in the original Act 10 fight, then in the recall, then in Walker's re-election fight. Walker earned accolades from Republicans not only in Wisconsin but nationwide. Today, he has an 80 percent approval rating among likely Wisconsin GOP voters, according to the most recent Marquette Law School poll. Trump had nothing to gain by coming to the state and dumping on Walker, even after Walker endorsed Ted Cruz.

2) Wisconsin Republicans take criticism of Walker personally. They don't just respect Walker. They take pride in themselves for helping him win. They sent him money, made phone calls for him, knocked on doors for him, defended him to their Democratic friends, and stuck with Walker when he was under fire. They've all been through the Long March together, and now they are enjoying Act 10's success. When they praise Walker's achievement, they're praising themselves, too. So when Trump attacked Walker, they saw it as an attack on themselves.

3) Badger Exceptionalism. Many Wisconsinites are fond of heaping praise on their state, and themselves, for being "different" from other states. In their view, Wisconsinites are more civil, more serious, and better informed than other Americans, and the state's politics is conducted on a higher plane. (This self-regard obviously does not extend to Wisconsin Democrats, who seemed to go insane during the Act 10 fight.) Charlie Sykes, the conservative radio host who is leading #NeverTrump forces here, told Fox Business recently that Wisconsin voters would provide "the firewall of rationality in this Republican madness." "I frankly do not think that Donald Trump is going to win in Wisconsin, because his brand of what you call 'gutter politics' may play elsewhere, but Wisconsin is different," Sykes explained. "And that is kind of the point I'm trying to make here, is that Wisconsin has a different political culture, our culture is different but also our politics are different here."

So in attacking Walker, Trump was wrong not just on the substance of Walker's achievement, but also wrong on the psychology of Wisconsin's Republicans. It's the kind of mistake that is hard to recover from.