PHOENIX (AP) — In a windowless conference room, Republican Senate candidate Martha McSally was asking executives at a small crane manufacturing company how the GOP tax cut has helped their business when one woman said: "I want to ask you a question about health care."

Marylea Evans recounted how, decades ago, her husband had been unable to get health insurance after developing cancer, forcing the couple to sell some of their Texas ranch to pay for his treatment. Now she was worried about Democratic ads saying McSally, currently a congresswoman, supported legislation removing the requirement th...