WHEN Jennifer Maggio was in her early 20s, she was raising two children by herself on the $750 per month that she earned as a manager at a furniture store in Vidalia, La. She went to college at night and was living in subsidized housing when she felt God urge her to make an unexpected choice. “I started tithing. To tithe while I was living on food stamps — that was a tough decision,” she said. “The conversation I had with God was: ‘You’ve got to be kidding me. This is about the pastor wanting a new truck.’ ”

She dropped a $75 check in the offering bucket. “I kept doing it, and the bills continued to get paid.” Within a year, she got a job offer from a bank in Baton Rouge and “went from food stamps to a six-figure income,” she said. Ms. Maggio credits God, not government assistance, with helping her climb out of poverty. She later married and founded Life of a Single Mom Ministries to help other women. She hates talking politics, but says she has always been an “extremely conservative Republican.”

Politically speaking, Ms. Maggio is unusual: in 2008 and 2012, three-quarters of single mothers voted for President Obama. It’s tempting to dismiss a Republican single mom as a dupe persuaded to vote against her own interests, a victim of what Thomas Frank called “the politics of self-delusion.”