I really do wish they would stop these stupid open primaries.
I'm serious, is that you Karl? It took me a while to figure it out but you're right there for Romney at every turn. Yep, I'm pretty sure you're a dyed-in-the-wool Romnian.
Your numbers are far off.
Santorum is winning Reagan Democrats in Northern Wisconsin (Obama won most of these counties in 2008). These are heavily white, working class voters. This includes Brown County (Green Bay).
Santorum is also slightly winning Dane County (Madison), largely because he is very strong with younger voters (UW-Madison).
If you think that 4% of voters can flip major metropolitan counties, you are very mistaken.