For Republicans in Wisconsin, it’s a time to be sentimental — and scared. BURLINGTON, Wisconsin — Picnics aren’t supposed to be maudlin. But last weekend, as they piled their plates with bratwurst and tipped back cans of Pabst Blue Ribbon at Speaker Paul Ryan’s annual Fall Fest, Wisconsin Republicans wrestled with their mortality as a powerhouse in state and national politics. Gov. Scott Walker, who is seeking a third term in November, delivered the biggest buzzkill. Believe the polls, he told the nearly 300 activists gathered here inside a tarpaulin tent in the middle of an apple orchard. Even the...