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 84 percent approval rating among Wisconsin GOP voters. 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.