This fall, millions of people learned in church that they could go to hell if they didn't vote for a certain presidential candidate or party platform. Millions more took in media advertisements sponsored by religious groups that made the same point.

Let us set aside the question about whether God takes sides in American elections. The more pressing fact about this kind of religious-political advertising is that you, dear taxpayer, are footing part of the bill.

According to a recent Pew survey, about 13% of regular churchgoers reported receiving "political information" at church services, and about half of those said they were urged to support a specific candidate or party. So, to use the language of marketing, church-based advertising reached somewhere between 8 and 16 million "eyeballs".

If candidates had to buy this kind of advertising – and they surely would if they could – it would cost them tens, or perhaps hundreds, of millions of dollars over the course of a campaign. And, of course, the money they raised and spent would all be subject to tax.

Religious organizations, on the other hand, are largely exempt from taxes.

Now, tax exemptions are really just another name for a public subsidy. If I don't pay my share of public expenditure on roads, law enforcement, defense and so on, the difference has to come from you. And it is for precisely this reason that the law forbids religious organizations, like all similar tax-exempt groups, from direct involvement in electioneering.

So, how do so many churches get away with breaking the law?

A number of fundamentalist Christian activists have an answer. Matt Barber, vice-president of the rightwing Liberty Counsel Action, spells it out in an op-ed for World News Daily titled "IRS Surrenders: Time for Churches to Get 'Political'". The Internal Revenue Service, he says, has given up on enforcing the law, so churches should just go ahead and flout it. If pastors get a letter from any liberal groups pointing out that electioneering will put their tax status in jeopardy, says Barber, "I suggest a singular use for it: bird-cage liner."

Barber is right about the IRS, at least. The IRS code (pdf) stipulates that tax-exempt groups "must not participate in, or intervene in, any political campaign on behalf of (or in opposition to) any candidate for public office".

So, when the IRS sits on its hands while Illinois Bishop Daniel Jenky commands all the priests in his diocese to read an anti-Obama letter at mass; when the IRS pretends not to be interested while Billy Graham runs full-page ads in national newspapers on the eve of the election whose message is a transparent endorsement of Mitt Romney; when the IRS has nothing to say about the fact that on 7 October, at least 1,000 pastors participated in "Pulpit Freedom Sunday" by explicitly endorsing political candidates from their pulpits – we can only suppose that the IRS has decided to ignore its own code.

That, at any rate, is the conclusion that the Freedom From Religion Foundation has come to. On 14 November, in a bid to get the IRS to live up to its own code, the FFRF filed suit against the IRS in a US district court.

In its complaint, the FFRF makes the argument that the IRS, by giving a special break from the rules on tax-exempt organizations to religious groups alone, has unfairly disadvantaged non-religious tax exempt organizations, like the FFRF itself. The FFRF also argues that the special treatment for religion amounts to an establishment of religion, in violation of the first amendment of the US constitution.

The FFRF's position is laudable, and whether or not the courts prove to be the right means at this time, its aim is true. But it doesn't address a still more important question that is bound to arise when looking over the recent history of faith-based political advertising: why are some of these religious groups tax-exempt at all?

When Thomas Jefferson and James Madison pushed through the Virginia statute for religious freedom in 1786, they were very clear that the use of public money to pay for private religion amounts to an impermissible establishment of religion. Jefferson wrote:

"To compel a man to furnish contributions of money for the propagation of opinions which he disbelieves and abhors, is sinful and tyrannical."

Over the past century, changes in the way taxes are collected have created a situation in which public subsidies can be delivered through inaction, rather than action. But the fact that such subsidies come in the form of tax exemptions doesn't mean that Paul is any less on the hook to pay for Peter's religion.

Advocates of politicized religion will say that they have the right of free speech, like anybody else, and that their beliefs compel them to take a stand on politics and policies. All of which is perfectly true and fine. What they do not and should not have is a right to have their free speech and political advocacy paid for out of the public treasury.

If such religious groups took themselves off the public dole, then the government would have no business telling them what they could or could not say during election season. It is for this very reason that the first amendment forbids the establishment of religion – so that government is not put in a position where it has to intervene in the exercise of religion.

To use language that Mitt Romney might understand: the problem is that religious organizations are "takers" – the recipients of government handouts and "gifts" – and some of them seem determined to elect those candidates who will work to keep the government money coming their way.