The fourth circle of Hell, as envisioned by Dante Alighieri in The Divine Comedy, is reserved for the avaricious and the profligate. It is where those whose lust for getting and spending knew no bounds in life are punished in the afterlife by being battered endlessly with heavy weights. Notable among the souls damned for their greed, Dante wrote, “were clergymen and popes and cardinals, within whom avarice works its excess.”

What disgusted the great poet in 14th-century Florence — money-grubbing hucksters masquerading as men of God — is just as disgusting in 21st-century America.

Comedian John Oliver is no Dante, but on his HBO program “Last Week Tonight” he recently ripped into the “prosperity gospel” of television preachers like Robert Tilton and Creflo Dollar, who aggressively solicit donations to finance lavish lifestyles. These sleazy televangelists, Oliver said, assure followers that “wealth is a sign of God’s favor, and donations will result in wealth coming back to you.” They call it “seed faith” — the belief “that donations are seeds that you will one day get to harvest.” And the more believers “seed,” the more God will reward them with riches and miracles.

The conviction that charity returns blessings to the giver has been a pillar of Judeo-Christian teaching for millennia, of course. The Hebrew prophet Malachi urged people to put God to the test by tithing unstintingly. Be generous in giving to the poor, he quotes God as saying, “and see if I do not open the floodgates of heaven for you, and pour down upon you blessing without measure.” In the Sermon on the Plain, Jesus exhorts his followers: “Do good, and lend, expecting nothing in return; and your reward will be great. … Give, and it will be given to you.”

Religious faith inspires extraordinary levels of charitable giving. As Oliver acknowledged, there are hundreds of thousands of congregations in the United States. Many are citadels of heartfelt goodness, genuinely devoted to feeding the hungry, clothing the poor, and loving the stranger. By contrast, the “prosperity gospel” televangelists Oliver takes down are genuinely devoted mostly to themselves. Creflo Dollar, for example, flaunts his Rolls-Royces and encourages his flock to send him money so he can buy himself a $65 million Gulfstream jet. Kenneth Copeland lives in a $6.3 million palatial lakeside villa.

How can anyone not be appalled by such swindlers? They pervert what is most beautiful and ennobling about religion to prey on the weak and gullible, and in so doing bring God’s name into contempt.

What seems to most infuriate Oliver, however, is that these television “ministries” are tax-exempt. He rails against the IRS for treating them as legitimate, and mocks the agency’s disclaimer that it “makes no attempt to evaluate the content of whatever doctrine a particular organization claims is religious,” as long as the beliefs are “sincerely held.” To prove how meaningless a standard that is, Oliver even set up his own “church” — Our Lady of Perpetual Exemption — and invited viewers to send him tax-deductible donations. Obviously, he isn’t the first person to discover some shepherds are interested only in fleecing their flock. The Senate Finance Committee investigated six leading televangelists in 2007. The Dallas-based Trinity Foundation has been investigating religious fraud since the 1970s. Scandals involving TV ministries have often drawn media coverage.

But federal law purposely makes it difficult for the IRS to investigate churches. This is not because Congress wants to encourage charlatans who exploit people’s faith to line their own pockets, but because of the longstanding American aversion to giving government the authority to pick and choose among faiths, or to distinguish sincere religious beliefs from insincere scams. In a report last month, the General Accountability Office concluded that the IRS lacked the internal controls to guard against the temptation to “select organizations for examination in an unfair manner — for example, based on an organization’s religious, educational, political, or other views.”

Perhaps such controls could be devised, though the long history of the IRS being used to harass ideological or partisan targets isn’t encouraging. To be sure, there are clear lines that ministries may not cross, such as a minister’s personal use of church assets or the endorsement of political candidates. And fraud is a crime, no matter who commits it.

But that still leaves a broad gray area that comes down to belief vs. baloney. “Prosperity gospel” may amount to contemptible nonsense, but many would say the same of Scientology or Christian Science or Santeria. Or, for that matter, Judaism, Christianity, and Islam. Should government be empowered to sort it out?

It is a bedrock principle of American life that discerning religious truth is no job for the state. Sleazeball televangelists deserve to be mocked and exposed and warned against — but not by the IRS. As the First Amendment secures John Oliver’s right to excoriate Creflo Dollar, it secures Dollar’s freedom to preach his gospel of greed. That’s a reasonable tradeoff in this imperfect world. As for the world to come, consult Dante.

Jeff Jacoby is a columnist for The Boston Globe.