Like so many Americans, Jenny Escolastico has watched wearily as the cost of living has risen, straining her household budget. But as a mother of two children under 5, she faces added pressure that could shape how she votes in November: childcare costs.

Escolastico's household outside Allentown, Pennsylvania, is relying solely on her husband's income. She's staying home with her children, at least in part because she simply can't afford to work.

"What I would be spending on childcare would be more than what I would be making if I were working full time,...