Winterset, Iowa - Beyond the silos, down the street from the Rexall Drug, a few steps from the movie theater and the bakery, and hard by the Ben Franklin five-and-dime sits the Northside Cafe, with its nine wooden booths and its 15 shiny circular stools along the counter. This noontime, the hand-scrawled sign outside speaks of chicken-fried steak, butternut-squash soup, bread pudding, homemade desserts, hot drinks - and Rick Santorum. The former senator from Pennsylvania won the 2012 Iowa caucuses. Here, a classic Iowa small town, is just the sort of staging ground Mr. Santorum put to good use four...