In other words, more than doing interfaith, many Americans are living interfaith. This culture change has given rise to a burgeoning number of smaller, activist interfaith groups, some of which are only very loosely identified with faith traditions, if at all.

“The old model was institutional bigwigs talking carefully to one another about theology. The understanding of what ‘multi-faith’ is and how to organize around it has broadened tremendously,” said David Roozen, director of the Hartford Institute for Religion Research, who has focused on interfaith research. “The dominant American attitude toward other faith traditions is indifference. . . . It can be a challenge for interfaith” institutions.

Activist groups

Younger interfaith types today are more interested in activism and often focus on particular policy issues. For example, some of the newer, small groups in Washington are Interfaith Youth for Climate Justice and Shoulder to Shoulder: Standing with American Muslims.

When these new, more activist groups are taken into account, the interfaith movement as a whole appears to be thriving. The Rev. Bud Heckman, who has been a leader of several key interfaith groups, said his research shows there are twice as many interfaith groups nationally as there were a decade ago. A recent Hartford Institute survey showed congregations are twice as likely to engage in interfaith worship today as they were 10 years ago.