Politico reports:

Spring elections in Wisconsin are typically low turnout affairs, but in April, with the nation watching the state’s bitterly contested Supreme Court race, voters turned out in record-breaking numbers.

No place was more energized to vote than Dane County, the state’s second-most populous county after Milwaukee. It’s long been a progressive stronghold thanks to the double influence of Madison, the state capital, and the University of Wisconsin, but this was something else. Turnout in Dane was higher than anywhere else in the state. And the Democratic margin of victory that delivered control of the nonpartisan court to liberals was even more lopsided than usual — and bigger than in any of the state’s other 71 counties.

The margin was so big that it changed the state’s electoral formula. Under the state’s traditional political math, Milwaukee and Dane — Wisconsin’s two Democratic strongholds — are counterbalanced by the populous Republican suburbs surrounding Milwaukee. The rest of the state typically delivers the decisive margin in statewide races. The Supreme Court results blew up that model. Dane County alone is now so dominant that it overwhelms the Milwaukee suburbs (which have begun trending leftward anyway). In effect, Dane has become a Republican-killing Death Star.

“This is a really big deal,” said Mark Graul, a Republican strategist who ran George W. Bush’s 2004 reelection campaign in Wisconsin. “What Democrats are doing in Dane County is truly making it impossible for Republicans to win a statewide race.”

In isolation, it’s a worrisome development for Republicans. Unfortunately for the larger GOP, it’s not happening in isolation.

In state after state, fast-growing, traditionally liberal college counties like Dane are flexing their muscles, generating higher turnout and ever greater Democratic margins. They’ve already played a pivotal role in turning several red states blue — and they could play an equally decisive role in key swing states next year. [Continue reading…]