A head to head comparison of the 2012 Wisconsin General Election gives us an idea of the break down of the voters.    

Barack Obama received 1,613,950 (53%) votes beating Mitt Romney who gained 1,408,750 (47%) by 205.200 votes in Wisconsin.

Mitt Romney won 37 counties whereas Barack Obama won 35 counties in the total of the 72 counties in the State of Wisconsin.

Presidential General Elections

During the 2012 General elections, over 122M total number of votes were cast. Barack Obama got 62,614,654 (62.6 Million) over Mitt Romney's 59,141,654 (59.1 Million). He won the popular vote by 3,472,979 (3.4 Million). His victory at the State of Wisconsin (with 1,613,950 votes) represents 2.5% of his popular vote victory. The remaining 49 states contributed to the remaining 97.5% popular votes victory.

Top 15 Counties in Primary Elections vs General Elections

All Candidates (General Elections)

These 15 counties play an important role in these Primary elections. If a candidate, can get a sizable majority in the largest counties (Milwaukee, Dane, Waukesha), it becomes very difficult to win majorities in the smaller counties without voter outreach and increased voter participation in them.

Top 15 Counties Comparison in Primary Elections vs General Elections

General Elections
Barack Obama

General Elections
Mitt Romney

Milwaukee and Dane, two of the larger counties voted in favor of Barack Obama, giving him a 301K vote advantage. On the other hand, Waukesha, another large county, voted in favor of Mitt Romney giving him a 83K voter advantage. Referencing the above table, a summation and comparison of the top 15 counties for both candidates indicates a 203K vote advantage for Barack Obama. However, steady marginal wins for Mitt Romney in the less popular counties wasn't enough for him to catch up, making Barack Obama gain an upper hand in the State of Wisconsin.

Related References: 2016 Wisonsin Primary Election Story, 2016 Wisconsin General Election Story, 2020 Wisconsin Primary Election Story, 2020 Wisconsin General Election Story