Religious groups need to back off partisanship to shore up confidence

"The church expects its members to engage in the political process in an informed and civil manner, respecting the fact that members of the church come from a variety of backgrounds and experiences and may have differences of opinion in partisan political matters," said spokesman Scott Trotter.

Despite First Lady Michelle Obama's view expressed at the recent African Methodist Episcopal Church's General Conference that there is "no place better" than church to discuss politics, research has shown that church leaders have noticed their dwindling numbers and have backed off politically themed sermons. In 2006, Putnam and Campbell found 32 percent of Americans attending a church heard political content in sermons at least once a month, compared with just 19 percent in 2011.

And Merritt warns if church leaders don't pay attention to the data and allow their congregations to function merely as voting blocs, it will cheapen the institution of religion and force those seeking a more sacred and spiritual experience to look elsewhere.

"If, however, the church recognizes what is happening, if the trends serve as a wake-up call," he says, "we might find the best days of Christianity are ahead of us."