Walker believes that the turning point in the fight may have been when protesters targeted his family home in the Milwaukee suburb of Wauwatosa. For middle-of-the-road voters, that crossed a line of civility and decency. But that line was crossed repeatedly as Walker’s oppositions morphed from petulant to obscene to threatening.

During one of protests in Madison in 2011 a video captured one demonstrator repeatedly shouting the F-word at 14-year-old girl who was speaking at a pro-Walker rally. On the floor of the State Assembly a Democratic state representative turned to a female republican colleague and shouted “You are f—-ing dead!

While the scorched earth tactics and massive rallies excited the base, they alienated independents and reinforced the loyalty of conservatives.

Over the next three years, Walker was re-elected twice.

The tactics of the left may also have accomplished that was once unthinkable: turning one of the country’s most reliably blue states red, even in presidential election years.