Two days after I won the democratic nomination in my U.S. Senate race, I received an email from a doctor at the University of Chicago Medical School.
"Congratulations on your overwhelming and inspiring primary win," the doctor wrote. "I was happy to vote for you, and I will tell you that I am seriously considering voting for you in the general election. I write to express my concerns that may, in the end, prevent me from supporting you."
The doctor described himself as a Christian who understood his commitments to be comprehensive and "totalizing." His faith led him to strongly...