If only non-Mormons voted in Utah in 2016, Hillary Clinton would have picked up her fifth-highest margin of victory of any state. If ballots from non-LDS voters were the only ones counted in previous elections, Utah would have handed Al Gore his largest win and Barack Obama would have bested adopted son Mitt Romney here.

Those are big ifs. And they really don’t have much connection to reality as members of The Church of Jesus Christ of Latter-day Saints make up two-thirds or more of Utahns who vote.

But former television reporter Rod Decker uses these statistics — based on research and polling from the Brigham Young University Center for the Study of Elections and Democracy — to make the central point of his new book, “Utah Politics: The Elephant in the Room.”

“Utah is the most religiously polarized electorate of any state in America,” Decker said during a recent talk about his book at the annual Sunstone Symposium. “It’s sort of a pale reenactment of territorial times. We have a Latter-day Saints party; We have a non-Mormon party. We call them different — now we call them Republicans and Democrats.”

This deep fracture of the Utah body politic is the elephant in the room in Decker’s title because, he writes, “it is the most important fact about Utah politics but is rarely mentioned.”

Such infrequent mention, Decker wrote, is because it may be “impolite” to bring up.

Some officeholders and candidates are highly offended by questions about religion, even accusing those who would make such inquiries of bigotry.

But, as Decker noted, “though religion has little place in political discourse, it determines political outcomes” in Utah.

Decker, now retired, was known during his decadeslong career as a straight-shooting, loud-talking newsman who didn’t suffer fools or hypocrites. He never sounded unsure of himself, no matter the topic or his degree of familiarity with it.

His voice comes through in his book, although at a lower decibel level. He also has lots more time and space than he ever did in his TV spots to back up his assertions — although some of them leave plenty of room for skepticism.

It’s Decker’s second book. His first was a novel, “An Environment for Murder,” published 25 years ago, a murder-mystery steeped in Utah’s sagebrush-rebellion politics.

His new work may not hold many surprises for those who closely follow local politics, but it does offer a solid framework to understand why things are the way they are.

Sexual revolution

In exploring the great divide, he traces the history illustrating its evolution and noting the long period when Utah’s politics were competitive and mirrored the nation. While the LDS Church dominated Utah in every way during the early years after the Mormon migration West, the political split along religious lines didn’t emerge until after the sexual revolution and the 1973 Supreme Court ruling legalizing abortion nationwide.

“In 20 presidential elections from statehood in 1896 through 1972, Utah voted with American majorities — that is, for the winner — 17 times. Only three states voted for the winner more often than Utah in those 20 elections,” Decker wrote.

Since then, Utah has never voted for a Democrat for president and in most elections gave the Republican candidate his largest margin of victory.

In his Sunstone talk, Decker summed it up bluntly (to the delight of his audience): “Latter-day Saints politics are a lot about sex. Specifically, they come from a resistance to the American sexual revolution.”

From the rapid rise in the number of adults having sex outside of marriage, to legalized abortion, widespread pornography and gay rights, America’s changing attitudes pushed conservative religious groups more and more to the Republican side of the spectrum — none more so than Latter-day Saints.

“So the morality changed, but Latter-day Saints didn’t change,” Decker said. “They are still the rear guard of that old 19th-century Protestant morality once invoked to imprison their polygamous forebears.”

What was a significant realignment in national politics — where evangelicals and other religious conservatives make up an estimated 25% of the electorate — was in Utah a “tsunami” because of the supersized LDS voting bloc, Decker said, “and we’re still surfing that way.��

Without an opposing political party with the numbers to effectively counter the LDS-dominated Republican Party, conservatives here have had their way enacting laws and policies that comport with their views of morality. But Decker points to the one force that has repeatedly stepped in to check that authority: the federal courts.

“In Utah, federal courts ended cable TV censorship, enabled teens to get birth control without telling their parents, devised a detailed code for Latter-day Saint seminaries in schools, banned prayer in public schools and at graduations, and overturned the rules for the church-owned [Salt Lake City] Main Street Plaza,” Decker wrote.

“Federal cases under federal statutes forced schools to accept gay student clubs; child protection services were for a time placed under a special court-appointed committee; judges liberalized welfare rules; the Utah State Prison was ordered to provide a sweat lodge for Native American inmates and a diagnostic unit for the mentally ill; state road projects were delayed” — think Legacy Highway — "and federal courts decided public land issues.”

This repeated thwarting of Utah policies over time created an adversarial view of federal courts in particular and Washington in general.

Downwinders

Such distrust of central government also was nurtured in what Decker calls “the Downwinders’ Tale,” which he describes as “a story partly true about how nuclear fallout inflicted cancer on southern Utahns.

Decker recounts some of the studies trying to determine the actual extent of cancer caused by fallout from atomic-bomb testing in Nevada. But such causation is impossible to prove and so he discounts most of the claims.

“Folklore flourished around fallout,” Decker wrote, discounting stories about pink clouds and fallout drifting down like snow from the atomic blasts — despite sworn testimony from residents who said they had personally witnessed these phenomena.

Decker maintains the stories were embellished and enlarged over time as “it fit the views of those Utahns who were increasingly opposed to the federal government.”

Another chapter of Decker’s book sure to stir controversy is his blunt verdict that school reform efforts in the state have failed and “Utah education policy is not successful.”

“Education spending," he wrote, “seems like an experiment in how little the state can pay and still maintain acceptable schools.”

He pointed to a big income tax cut pushed by then-Gov. Jon Huntsman in 2007 as causing “long-term harm” to public schools while primarily benefiting wealthy Utahns.

Pointing to tax decreases, the shift of some public education money to higher education beginning in the 1990s, and the diversion of revenues to highways, Decker accuses Utah politicians of plotting to “pilfer education money” and “keep rising revenues away from schoolchildren.”

Decker makes at least one demonstrably erroneous claim — that as a result of state court reforms, “almost all” justice court judges are now lawyers. More than four of 10 are not attorneys, according to the Utah Courts website.

Overall, though, Decker presents solid evidence and sound logic for his observations. And he uses science as a metaphor for the way Utah can be viewed, comparing the state to an experimental control group “preserved, in part, from American change” and a chance to see what “a more socially conservative America might have looked like.”

While he refers to the total political domination of Latter-day Saints in Utah as seemingly immovable, in his recent Sunstone appearance he allowed that it’s anyone’s guess what the future holds.

Addressing a question about Utah voters bucking the church on the medical marijuana initiative last year, he noted “that was maybe a straw in the wind that things are changing.”

But, he noted, “Latter-day Saints get out and vote more than other people and that’s a large part of their power. Young people don’t get out and vote. If young people who aren’t Latter-day Saints got out and voted, then that would be something of a challenge to the church — maybe even in parts of Utah.”

Editor’s note • Former Gov. Jon Huntsman is a brother of Paul Huntsman, owner and publisher of The Salt Lake Tribune.