Republican presidential candidate Ben Carson speaks during the first Republican presidential debate at the Quicken Loans Arena Thursday, Aug. 6, 2015, in Cleveland. (AP Photo/John Minchillo)

On July 8, 1838, Joseph Smith, the founder of Mormonism, told his followers that he had received a revelation from God, on the subject of tithing.

The Lord, Smith told his congregation, had commanded his people to pay one-tenth of their income, annually and forever, to the church bishop.  "All those who gather unto the land of Zion, shall be tithed of their surpluss (sic) properties," the revelation said, "and shall observe this Law, or they shall not be found worthy to abide among you." A decade later, a contingent of Mormons trekked to Utah and staked out a community where church and government intertwined, and they made tithing the law of the land.

Thus began perhaps the only period in American history when someone implemented the tax plan that Republican presidential candidate Ben Carson is proposing today.

"We need a significantly changed taxation system," Carson said in the prime-time GOP debate last week. "And the one that I've advocated is based on tithing, because I think God is a pretty fair guy. And he said, you know, if you give me a tithe, it doesn't matter how much you make. If you've had a bumper crop, you don't owe me triple tithes. And if you've had no crops at all, you don't owe me no tithes. So there must be something inherently fair about that.

"And that's why I've advocated a proportional tax system. You make $10 billion, you pay a billion. You make $10, you pay one. And everybody gets treated the same way. And you get rid of the deductions, you get rid of all the loopholes."

What Carson is broadly advocating is a 10 percent flat tax, the details of which remain somewhat hazy, rooted in the Biblical concept of giving one-tenth of your belongings to God. That practice, known as tithing, first appears in Genesis and recurs in various forms throughout the Old Testament. Mormons and members of many Protestant churches continue it today, along with some Catholics.

The U.S. government has never employed a tithing-like income tax structure. But the Utah Territory effectively did for several decades in the mid 1800s, under the leadership of Brigham Young. Young was the head of the Church of Jesus Christ of Latter-Day Saints and also, for many years, the territorial governor; even after he left office, the church supplied most of what we'd think of today as core government services, such as building roads and educating young people.

"Essentially, the church was the government of Utah, for all practical purposes, for quite a few decades," says John Turner, a historian at George Mason University and the author of Brigham Young: Pioneer Prophet. "So there was an expectation that one would pay 10 percent of one's income as taxes."

That 10 percent, Turner explains, wasn't usually paid in cash, which was fairly scarce in the territory. Instead, people paid with livestock or produce. They were also expected to donate one out of every 10 days of labor to the church, meaning they worked on church construction or other projects. The population was generally quite poor, Turner says, but wealthier people sometimes paid others to do their tithed work for them.

The system worked in a lot of ways, Turner says. It mobilized resources to settle and develop the territory, and it provided a type of welfare for the poorest people in Utah, because bishops distributed a lot of the tithed food and animals to the poor. It also helped to foster a sense of "pride in taking part in tithing" among poorer Mormons, Turner says, - the sort of ethic Carson sometimes says his plan will help engender.

It also had problems: Young constantly complained that tithers were giving him "the worst of their animals," Turner says.

Tithing remains a tenet of the LDS church, but it eventually gave way as Utah's unofficial system of taxation, as the federal government slowly but surely drove a wedge between the church and the (soon-to-be) state near the end of the century.

Even before that, though, some parts of  Utah had moved beyond tithing to another Bible-based taxation system, called the Law of Consecration. It mimicked a practice of early Christians, reported in the Book of Acts in the New Testament. Smith reported the details of the law, as it applied to his followers, had been given to him in a revelation in 1831.

Under the practice, people in a community handed the church ownership of all their possessions. The church then gave each member of the community the use of enough property to provide for the needs of their families.

It was, in effect, a religious form of communism. So, not likely to inspire a Republican tax plan any time soon.