Why did Richard Nixon win Wisconsin in 1960 and 1968?

[Alcibiades]

Because Wisconsin was a generally Republican-leaning state in this period. This is not surprising considering its demographics; comparing it to its neighbours, it was more German and less Scandinavian than Minnesota, and less industrial and urban than Michigan. Wisconsin would not vote consistently more Democratic than the nation as a whole until the Farm Crisis of the 80s, which had the effect of shifting the hitherto mostly Republican Driftless region into the Democratic column.

In this light, then, the real outlier is Carter winning it in 1976 (in large part as a result of a very strong performance in the northwest of the state), which was widely considered the biggest individual state result shock at the time. 1972 is also interesting, though perhaps more explicable: states do weird things in their lean relative to the national vote share during landslides, and in general Wisconsin had more of the demographics that McGovern held up well with and even gained among — rural Upper Midwesterners as well as maybe something of a Dane County effect — while relatively lacking the traditional Democratic groups he slid most among.