In fact, should Trump lose, it could be in part because of one very big miscalculation: Walker remains very popular among Wisconsin Republicans, but the real estate mogul continues to attack him. The highly respected Marquette Law School Poll this week put the governor’s approval rating at 80 percent among likely primary voters.

“It was the most absurd strategy I’ve ever seen,” said Mark Graul, an unaligned GOP strategist in the state “You attack somebody with high favorables, who’s won three gubernatorial elections in four years? It makes no sense to me.”…

“What the talk radio folks did was give Cruz a ground game he may not have had — they bring that listener audience that becomes boots on the ground,” said Brandon Scholz, a longtime GOP strategist and lobbyist in the state. “Walker’s endorsement is the push that was needed to bring a lot of those undecideds home.”