Sullivan shrewdly points out (emphasis mine):
A story that shows the McCains' genuine compassion and faith is embellished over the years to make the story a little more perfect, a little more salient, a little better as a narrative. It's especially important to add these embellishments when your goal is to appeal to a fundamentalist base, when your own prickly, personal and private faith isn't very marketable. And when your adopted daughter is Bangladeshi, and when that fact has been disgracefully used against you by the Bush machine in 2000, and when some fringes of your base get queasy about multi-racial families, what better way to describe the adoption than as something Mother Teresa herself "implored" you to do? More interesting: the first actual reports of this event do not mention this fact. They are added later.