Contrary to statements by Walker, the Wisconsin Supreme Court election is not proof of how evenly split the state is for three critical reasons: Prosser was expected to win by large margins, everyone didn't vote, and the money spent in support of Prosser far outweighs the money spent in support of Kloppenburg. This election became a referendum on Walker's plans when Prosser signaled he would support the governor's plans, because he has proven to be a conservative vote on the court. The movement wasn't necessarily in support of Kloppenburg as much as it was against Prosser's conservative bias on the court. If this election shows anything, it shows that there's a swell of energy against Walker's plans for Wisconsin.
Prosser is an incumbent Supreme Court Justice. Incumbent Supreme Court justices rarely lose elections, only five justices have lost a re-election in Wisconsin history. Also, Kloppenburg had little name recognition before February. In fact, Prosser received 55% of the vote in the February primary, while Kloppenburg received only 25%. That left less than two months for Kloppenburg to reach double the number of voters and grab 5% of the electorate from Prosser. A lot of energy and momentum was needed just to reach Prosser's level of support, and the margin in favor of Kloppenburg would likely have increased with more time.
Not everyone voted Tuesday. Of the over 3 million registered voters in Wisconsin, about a third voted in the Supreme Court election. Voters are motivated for various reasons, and non-voters are similarly not motivated for various reasons. So, unless a very large portion of the people of Wisconsin vote, it's difficult to say whether the results of the election truly reflect the views of the people of Wisconsin. This is why pollsters put lots of effort into properly selecting the people they survey. Even though their sample of the state is generally quite smaller than any election, the principles in polling still apply to election results. This election, whose results differ from all polling which has shown a stronger majority disapprove of Walker, most likely doesn't truly reflect the views of the people of Wisconsin.
The amount of money spent in support of Prosser far outweighed the money spent in support of Kloppenburg. According to the Wisconsin Democracy Campaign, the groups in support of Prosser outspent the few groups in support of Kloppenburg nearly 2-1. Also, since the candidates accepted public campaign financing, the ads from the money spent by these groups were the only voice most voters heard. Based on that alone, one would think a large majority would have voted for Prosser. The fact that the election is so evenly split shows that the energy is behind the movement against Walker's plans, since there was so much to overcome.
As part of Walker's argument that the election doesn't show that a majority of Wisconsin disapprove of his plans, Walker said the election results were "largely driven by Madison, and to a lesser extent Milwaukee." He also basically said Madison is in its own world.
I don't know what Walker was thinking when he said that, but, as examples, La Crosse, Eau Claire and Ashland counties voted with strong support for Kloppenburg. Those counties are quite far from Madison and Milwaukee. Kloppenburg couldn't have won if most of the state didn't support her. Several counties surrounding Milwaukee voted for Prosser in similar proportion to the votes for Kloppenburg from Madison. So, Madison didn't control this election. Any one county in Wisconsin could have stayed home, and the results would be much different. In fact, of the counties who voted for Kloppenburg, 18 voted for Walker just a few months ago.
Kloppenburg's victory over Prosser can't be overstated, even if she nearly lost, it would have been a major feat. Such a victory has only been achieved 5 other times in over 150 years, and with very little name recognition compared to Prosser, Kloppenburg was a huge underdog. Prosser ran uncontested the last time he was elected. If Walker hadn't attacked workers' rights and other Wisconsin values, Prosser would probably have won by a landslide. Instead, Wisconsinites worked to spread the word and vote for an independent justice on the Wisconsin Supreme Court, and won.
Updated: (April 7, 3:47pm) Corrected the number of counties that had voted for Walker and then voted for Kloppenburg from 19 to 18 and changed the link to refer to a correct article.
Updated: (April 19, 7:35pm) Changed source of spending numbers from the Brennan Center to a more recent report by the Wisconsin Democracy Campaign.