Obama did not grow up in a religious household and became a practicing Christian as an adult. He has written more extensively about his spiritual awakening than almost any other modern president, addressing it in two books before he was elected to the White House and in more than a dozen speeches since. His faith had been central to his identity as a new kind of Democrat who would bring civility to the country’s political debates by appealing to Republicans through the shared language of their Judeo-Christian values.

With just one year left in his second term, Obama now holds a different distinction: No modern president has had his faith more routinely questioned and disparaged. Recent polls show that 29 percent of Americans and nearly 45 percent of Republicans say he is a Muslim.

He has repeatedly said in recent months that one of his biggest regrets is that he will leave behind a country that has grown more polarized and distrustful during his two terms in the White House. “There’s all this goodness and decency and common sense on the ground, and somehow it gets translated into rigid, dogmatic, often mean-spirited politics,” Obama said in a recent interview.

To understand why he so deeply believed that he could close that gap and why he largely has been unable to do so, it is essential to understand his faith and how it shapes his politics. That faith also explains why he has not given up.