The data provide fodder for both sides. On the one hand, religious Americans are somewhat less tolerant of free speech and dissent. As just one example, in our survey we asked Americans whether someone should be allowed to give a speech defending Osama bin Laden or al-Qaeda. While most Americans said yes - we are indeed a tolerant people - religious Americans were slightly less likely to say so. The same pattern is true for many other measures of tolerance: While, in general, Americans are quite tolerant, religious Americans are less tolerant than their secular neighbors. Furthermore, the "tolerance edge" among secular Americans cannot be explained away by some other attribute that they share. Statistically, we have accounted for every imaginable way that religious and secular Americans differ from one another. When we do so, the story stays the same.

More religious, more involved

However, on the other side of the ledger, religious people are also "better neighbors" than their secular counterparts. No matter the civic activity, being more religious means being more involved. Take, for example, volunteer work. Compared with people who never attend worship services, those who attend weekly are more likely to volunteer in religious activities (no surprise there), but also for secular causes. The differences between religious and secular Americans can be dramatic. Forty percent of worship-attending Americans volunteer regularly to help the poor and elderly, compared with 15% of Americans who never attend services. Frequent-attenders are also more likely than the never-attenders to volunteer for school and youth programs (36% vs. 15%), a neighborhood or civic group (26% vs. 13%), and for health care (21% vs. 13%). The same is true for philanthropic giving; religious Americans give more money to secular causes than do secular Americans. And the list goes on, as it is true for good deeds such as helping someone find a job, donating blood, and spending time with someone who is feeling blue.

Furthermore, the "religious edge" holds up for organized forms of community involvement: membership in organizations, working to solve community problems, attending local meetings, voting in local elections, and working for social or political reform. On this last point, it is not just that religious people are advocating for right-leaning causes, although many are. Religious liberals are actually more likely to be community activists than are religious conservatives.

As with tolerance, we wondered whether religious people's do-gooderism is owing to something else about them. Maybe it is because women are more religious than men, and women are better neighbors. Or maybe it is because religious people are older - and so on. Again, the results hold steady even when we account for these potential counter-explanations. In fact, the numbers we report above already adjust for the demographic differences between religious and secular Americans.

Interestingly, one's particular flavor of religion - being a Baptist, a Buddhist, or anything else - makes no difference in these results. In fact, even people who claim no religious affiliation but still attend worship services occasionally are more civically involved than those who never attend at all.

One might think, as did we, that religious people do good because of what they hear from the pulpit. After all, the world's religions all teach a version of the Golden Rule: Treat others as you would be treated. Perhaps stories like the Good Samaritan inspire good citizens. Or perhaps good deeds are motivated by a desire to go to heaven. Or maybe people want to avoid the punishment of God's judgment for not being nice.

However, it turns out that religious beliefs - of any kind - do not affect any form of civicness. We examined the possible impact of 25 different religious beliefs on civic behavior, and none explains religious Americans' good neighborliness.

Friends matter greatly

What, then, does explain why religious Americans are good citizens? The answer lies not in their beliefs but their friends. Specifically, having friends at church (or synagogue, temple, mosque, etc.) fosters neighborliness. While having more friends is, for civic purposes, better than having fewer friends, what matters most is having friends within a religious congregation. And the type of congregation does not matter. Friends found in Catholic parishes, Jewish synagogues, Protestant churches, Mormon wards - and every other type of religious grouping - all produce the same civic effect. Even people who are not very religious experience a civic boost if they are enmeshed in a religious social network. (Think of religious skeptics who have befriended members of their believing spouses' congregations.)

What is it about friends-at-church that fosters good citizenship? It could be that requests to get involved carry more moral weight when they come from someone you know through your congregation rather than work or your bowling team. Or perhaps religious congregations simply foster peer pressure to do good. At this point, we do not know the precise magic civic ingredient in religious friendships.

Not knowing exactly how religious friendships foster good neighborliness thus leaves open the possibility that the same sort of effect could be found in secular organizations. But they would probably have to resemble religious congregations - close-knit communities with shared morals and values. Currently, though, such groups are few and far between. (Communes might qualify, for example.)

So, does religion help or harm our civic life? The answer is a little of both. Religion means less tolerance but more neighborliness. And the reason for that neighborliness is not found in what religions teach but in the communities they form.

All of this should give both religion's fans and foes food for thought.

----David E. Campbell is an associate professor of political science at the University of Notre Dame. Robert D. Putnam is professor of public policy at Harvard University. They are co-authors of American Grace: How Religion Divides and Unites Us.