City of Milwaukee turnout was 72% of voting-age citizens in the 2012 presidential race, but only 47% in the 2010 midterm.
So even though the city voted overwhelmingly Democratic in both cases, Milwaukee’s value to Democrats was far greater in the presidential race. The party’s winning margin in the city was 90,000 votes in the 2010 governor’s race but more than 170,000 votes in the election for president two years later.
Via Milwaukee turnout one of the keys to Walker-Burke election @ JS Wisconsin Voter Blog.