When Sen. Harry Reid (D-Nev.) steps down from the Senate in early 2017, Mormonism will lose its highest-ranking elected official -- and the most high-profile example that yes, there is such a thing as a Mormon Democrat.

Mormons are the most Republican religious group in America, and they are moving to the right. A 2007 Pew study found about 66 percent identify with the party. By 2012, Pew found that figure had risen, and 74 percent of Mormons identified as Republican.

During an address at Brigham Young University in 2007, Reid talked about what it was like being a Democrat in a deeply Republican faith.

"It is not uncommon for members of the Church to ask how I can be a Mormon and a Democrat," he said. "Some say my party affiliation puts me in the minority of our Church members. But my answer is that if you look at the church membership over the years, Democrats have not always been the minority, and I believe we won't be for long. I also say that my faith and political beliefs are deeply intertwined. I am a Democrat because I am a Mormon, not in spite of it."

It's true that Mormons haven't always been as Republican as they are today. Here's a chart from Seeking the Promised Land: Mormons and American Politics by David Campbell, John Green, and Quin Monson (it's a must-read for anyone interested in the intersection of Mormonism and politics) that shows how that's changed since 1896. It specifically tracks only Utah Mormons, but it's telling.

When Reid was first elected to Congress in the 1980s, about 70 percent of Utah Mormons voted Republican. By 2012, that figure reached 90 percent -- though having a fellow Mormon on the ticket in 2012 certainly could be a factor in the record-breaking percentage.

Reid's prediction that Democrats won't always be in the minority in the church came several years before the Church of Jesus Christ of Latter-day Saints would show it doesn't toe the party line on some hot-button Republican issues. In 2010, the church backed immigration proposals that kept families together and focused on criminal activity rather than federal violations, and this year, Utah's LGBT and religious protections legislation was applauded by LGBT groups, while social conservatives were mostly unimpressed.

Mormon Democrats are more likely to be women and less likely to be white, mirroring Democratic demographics nationally, but unlike national trends, they're also more likely to be older. Mormons over the age of 65 are 51 percent Republican, compared with 69 percent of those under 30.

So while Mormons very well may one day become more Democratic, it just might take awhile for a new generation to start voting. But by then, they won't have the high-profile example of Reid to look to.

The Senate minority leader announced that he will not run for reelection in 2016. PostTV took a look back at Sen. Harry Reid’s (D-Nev.) time serving in the Senate. (Pamela Kirkland/The Washington Post)