Palestinian educator Dr. Maria Khoury geared up for the winter chill with what was at the time a meaningless purchase: a black silk scarf with silver stripes to drape around her neck.

But now, on her daily excursions from the West Bank's Taiba to nearby Ramallah, the scarf serves as a political symbol of the changing times.

"Since Hamas took over, I cover my head in Ramallah," she says. "I don't feel comfortable."

In the largely cosmopolitan Ramallah, though they comprise some 10 percent of the population, Christians are becoming less and less visible...