SALT LAKE CITY, UTAH— Evangelical Christians have long regarded Mormonism with suspicion. But many evangelicals are now trying to reconcile supporting a Mormon candidate for president while rejecting the teachings of his faith's 19th century American prophet, Joseph Smith Jr.
"Joseph Smith had 34 wives, 11 of whom were currently married to other men when he took them as wives!" says Rob Sivulka, who goes for the jugular in his polemic outside the headquarters of the Church of Jesus Christ of Latter-day Saints.
The church disavowed polygamy in 1890.
But Latter-day saints, also known as Mormons, hear this kind of thing a lot.
Sivulka's evangelical group is one of many in America trying to persuade Mormons that their faith is wrong.
"Father, Son and Holy Spirit, thank you so much," adds Sivulka. He is married to a former Latter-day Saint. He says he loves Mormons.
But he says "I consider them to be false Christians. In contrast to what the Bible teaches in Isaiah 43:10."
He says the Mormon church emphasizes Jesus to lure converts.
"I’m concerned about my own Christian brothers and sisters that are getting hoodwinked into joining this, what I would call a cult," says Sivulka.
The Church of Jesus Christ of Latter-day Saints rejects the charge. It says the teachings of its 19th century prophet, Joseph Smith, are consistent with the Bible.
But Smith's writings de-emphasized original sin and said believers could achieve divine status. Mormon history professor J.B. Haws says non-Mormons did not like that message.
"Joseph Smith's work was - not intentionally - but it ended up being polarizing,'' he says.
A historical theme park recreates the lifestyle of Mormons who fled to Utah after Smith's murder in 1844.
"How do you think you'd sleep on that bed?" says Jennifer Leeds, who adds some non-Mormons think the church still practices polygamy.
"They ask how many moms I have, and I respond I only have one and I also have one dad," she says.
Sivulka carries on his crusade. But when it comes to politics, he supports Mitt Romney for president, albeit grudgingly.
"Yeah I could trust him to a certain extent," says Sivulka. "I certainly wouldn't trust him with my eternal soul."
Mormons themselves admit it would be hypocritical for them to condem proselytizing.
They go as missionaries to far-flung lands and knock on doors of prospective converts.
Eric Johnson and a fellow evangelical are giving Mormons a taste of their own medicine in a majority Mormon town. And they get a taste of rejection.
"I love it when missionaries come to my house, I don’t slam the door in their face," says Johnson.
Johnson came to Brigham City, Utah, as its residents were celebrating the construction of a new temple.
"We don’t believe we are anti-Mormon because if we didn’t care about Mormon people then we wouldn’t even be doing this," adds Eric Johnson, an evangelican.
"Sometimes the best approach is just to ignore them,'' says J.B. Haws. And sometimes it is not.
Tensions between Mormons and evangelical Christians go all the way back to the founding of the Church of Jesus Christ of Latter-day Saints. But with an election coming up, they seem to be willing to put aside, at least their theological differences.