During just a single generation, the landscape of American religious belief and behavior has undergone sweeping changes. A growing share of the adult public abstains from regular religious practice. They profess greater doubts about the existence of God and no longer identify with any established religious tradition.[xi] A recent survey found that young adults have far less robust religious experiences compared to previous generations.[xii] And although surveys vary in the exact rate of religious decline, there is no disagreement about the trajectory of American religion.
Among both Democrats and Republicans, there are signs of weakening religious attachments, and nonreligious Americans have increased in number. However, the religious decline is occurring much more rapidly among Democrats than Republicans. Across measures of membership, salience, and affiliation, Democrats have experienced a steeper drop in their level of religious commitment.
Religious membership among the public has plummeted over the past decade, but the decline has proceeded unevenly (Figure 4).[xiii] Democratic religious membership has fallen further than among Republicans, more than doubling the partisan gap in religious membership over the past two decades. Today, less than half (45 percent) of Democrats report being a member of a church, synagogue, mosque, or other religious congregation. In the late 1990s, more than seven in 10 (71 percent) Democrats reported that they belonged to a church or other place of worship.
Republican religious membership has also fallen in the past couple of decades, although not nearly as far. Sixty percent of Republicans say they are members of a religious congregation, compared to 77 percent two decades earlier. This differential rate of decline has substantially widened the partisan gap in religious membership over the past two decades.
The rate of change when it comes to the personal importance of religion in Americans’ lives reveals a similar partisan gap. Only 43 percent of Democrats today say religion is a very important part of their lives—a roughly 20 percentage point drop from the late 1990s (Figure 5). In 1998, nearly two-thirds (65 percent) of Democrats said religion was very personally important to them.
The drop in religious salience among Democrats stands in marked contrast to Republicans, whose views of religion have not changed over the past two decades. From 1998 to 2021, at least six in 10 Republicans have reported that religion is very important to them. Today, 65 percent of Republicans say that religion is very relevant in their lives.
The past 20 years have also witnessed growing religious diversity among the Democratic Party. Today, Democrats include a growing number of non-white Christians and people who belong to non-Christian religious traditions, such as Buddhism, Hinduism, Islam, and Judaism. Until recently, the Democratic and Republican parties were composed of a majority of white Christians.[xiv] In 1998, nearly six in 10 (57 percent) Democrats identified as white Christians, but, roughly 20 years later, white Christians account for only about one in three (31 percent) members of the party.