Is Romney nicer because he’s Mormon?

Mitt Romney’s tax returns prompt this question. According to those documents, which he released recently, Romney gives at least 10 percent of his earnings of about $20 million a year to the Mormon Church.

He tithes, in other words, in accordance with the expectations of his church’s leaders and the biblical command from Leviticus: “All tithes from the land, whether the seed from the ground or the fruit from the tree, are the Lord’s; they are holy to the Lord.” A tithe is 10 percent of what you earn, a portion seemingly calculated to hurt the giver, but not so much that it’s impossible to give.

Sociologists have studied the correlations between religiosity and giving and niceness, and have discovered that the more people give, the nicer they are. That is to say, generous giving to religious institutions correlates to giving to secular charities (the Boy Scouts, say, and the American Heart Association), which correlates to volunteerism and civic mindedness and, broadly speaking, altruism.

“Religiously observant Americans,” write Robert Putnam and David Campbell in their 2010 book, “American Grace,” “are better neighbors and better citizens than secular Americans — they are more generous with their time and money, especially in helping the needy, and they are more active in community life.” Even Romney’s detractors admit, as a conservative evangelical operative did to me recently, that he’s “a fundamentally decent guy.”

Religious people are, in other words, nicer.

As religious affiliation in America declines, so, correspondingly, does generosity. According to Empty Tomb, an Indiana outfit that collects data on church giving, the average American gave just 2.38 percent of annual income to church in 2009, the lowest percentage since 1968.

Overall, Americans give between 2 and 3 percent of their income to charity, according to the Philanthropy Roundtable, but in the first few years of the recession, that number dropped, too. Newt Gingrich gave just $81,000 — 2.58 percent of his $3.1 million income and a fraction of his 2005-06 tab at Tiffany’s — to charity in 2010. No one would ever accuse the former House speaker of being too nice.

This correlation between religious giving (and, I would argue, giving in general) and niceness, or altruism, isn’t just a cute trope dreamed up by academics. In an America defined by a dramatic lack of fairness, at a time when that lack of fairness is a top-tier political issue, the question of who’s giving to what, and how much, matters. And it matters not just in the “thousand points of light” sense: The more individuals and corporations give, the less the government has to.

Giving, and giving until it hurts, forces you to recognize that, like a parent, you’re responsible for other people — whether in your own community or around the world. When you lay down your money, you say, “This (church sanctuary, child, environmental hazard) is my problem.” Providing a sense of interconnected obligation is traditionally what religious communities have done best, and it is no surprise that the religious groups that are growing fastest in America — Mormons, Pentecostals, certain sects of  Jews — are those that make demands on their members’ time and money.

“People understand that a spiritual practice and a religious community require that we give of ourselves in ways that are not always comfortable,” says Rabbi Sharon Brous of the Los Angeles synagogue IKAR. “It’s about stretching yourself beyond what you imagine is even your capacity. What draws people into religious life is that desire to be more than you would otherwise be.” (Taxes, Brous argues, are another kind of collective obligation, and she wishes Romney had paid more. “On one hand, I really admire his sense of obligation to his immediate community, but I would offer that perhaps he might adopt a more expansive notion of what community is.”)

To squeeze the most out of the metaphor: The country suffers under a crisis of not-niceness. Politicians critique the income gap and partisan bickering, but all — including Romney with his 15 percent tax rate — want to give less and get more. The president’s tax returns are illuminating here.

On 2010 income of $1.7 million, President Obama paid 26 percent in taxes and gave $245,000, or 14 percent, to charity — including $131,000 to the Fisher House Foundation, which allows the families of American veterans to reside near loved ones during vets’ hospitalizations.

“Nice” might not be the first word that springs to mind when envisaging the president nor “religious.” But when he ran for president in 2008, he often used the biblical phrase “I am my brother’s keeper, my sister’s keeper,” and in 2010 he put his money where his mouth is.