Most famously, Mormons have "reacted with fervor when LDS leaders have mobilized them around such political issues as opposition to the Equal Rights Amendment in the 1970s and to same-sex marriage in the 2000s," Campbell writes in an email, including Mormons' involvement in the Proposition 8 campaign in California.
But Campbell points out that leaders of The Church of Jesus Christ of Latter-day Saints also have "moved Mormons' political opinions to the political left."
Campbell and his co-authors tested LDS reactions after they read statements from church leaders supporting two issues commonly associated with the political left — a municipal statute in Salt Lake City barring discrimination against gays and lesbians and a compassionate immigration policy.
"In both cases, when Mormons read statements attributed (accurately) to the [governing] LDS First Presidency, their opinions move toward the church position," Campbell concludes from the research. "The Mormons whose attitudes move the most are those who are most 'orthodox' — have the strongest level of belief and activity in the church — even though orthodox Mormons are also the most likely to be conservative Republicans."
In other words, Campbell says, "they put their religion over their party."
Though the vast majority of Latter-day Saints are Republicans, the faithful's devotion to the GOP is "not set in stone," he says. "As our research has shown, Mormons follow their leaders — to the left and the right."
And part of their religion encourages taking part in politics. Earlier this month, the First Presidency issued a letter to be read over the pulpit to Mormon congregations throughout the United States, urging members to be informed, get involved and vote.
"Latter-day Saints as citizens are to seek out and then uphold leaders who will act with integrity and are wise, good and honest," the letter advises. "Principles compatible with the gospel may be found in various political parties and candidates."
In a previous statement on political neutrality, the Utah-based faith says it does "reserve the right as an institution to address, in a nonpartisan way, issues that it believes have significant community or moral consequences or that directly affect the interests of the church."
That doesn't mean the church expects Mormon politicians to line up behind its positions — though many may do so.
"Elected officials who are Latter-day Saints make their own decisions," says the neutrality document, "and may not necessarily be in agreement with one another or even with a publicly stated church position. ... These officials still must make their own choices based on their best judgment and with consideration of the constituencies whom they were elected to represent."