It's just before / after. I just took the plot from somewhere else, a vertical line in February 2011 would have been more to my liking: before February 2011 Wisconsin followed the US trend, afterwards it stagnated. In February 2011 Wisconsin's passed their job creation laws.
In other words, their governor failed thoroughly, yet remains in office because some people paid a lot of money to obscure this simple fact. Sounds like plutocracy to me.