Books and the Presidential Campaign

Katie Couric asked the presidential candiates which single book they would take with them to the White House, aside from the Bible. Read about it here.
Barack Obama and Mitt Romney cited recent history books. Obama picked Team of Rivals, a biography of Abraham Lincoln by Doris Kearns Goodwin. Mitt Romney picked John Adams by David McCullough. I was pleased by their picks, because I suspect they chose books they actually had read and enjoyed.
I was less impressed by the old safetys. John McCain named Wealth of Nations by Adam Smith. Rudy Giuliani and Hillary Clinton both wanted The Federalist Papers.
Mike Huckabee, on the other hand, picked a book I'd never heard of, called Whatever Happened to the Human Race. A little research on my part reveals that this is a serious philosophical book with a Christian orientation on life issues. Barnes and Noble says:

In this moving book, the renowned pediatric surgeon and Surgeon General of the United States, C. Everett Koop, M.D., joins with one of the leading Christian thinkers of our day, Francis A. Schaeffer, to analyze the widespread implications and frightening loss of human rights brought on by today's practices of abortion, infanticide, and euthanasia. They see the present as a crucial turning point. Choices are being made that undermine human rights at their most basic level. Practices once labeled "unthinkable" are now considered acceptable. The destruction of human life, young and old, is being sanctioned on an ever-increasing scale by the medical profession, by the courts, by parents, and by silent citizens.

Meanwhile, Bill Moyers asked his viewers which book they would recommend for the president to read. A lot of people submitted answers here. I don't see too many interesting suggestions though, and some of the answers are just silly.
What would I suggest? The first book that popped into my head was Gilead by Marilynne Robinson, which isn't about politics or history or anything like that. It's a short, lyrical novel about a country minister who is dying and writing a letter to leave to his young son. To me, the novel is about humility and the limits of knowledge, and how good-hearted people can disagree vehemently on the best way to solve problems. This was more of an intuitive choice; it's just the first thing I thought of. If I think of something more apropos, I'll post again.